INDENTURE

Exhibit 4.1

EXPRESS SCRIPTS, INC.,

AS ISSUER,

ANY GUARANTORS PARTY HERETO,

AND

UNION BANK, N.A.,

AS TRUSTEE,

INDENTURE

DATED AS OF JUNE 9, 2009

DEBT SECURITIES

TABLE OF CONTENTS

Express Scripts, Inc.

Certain Sections of this Indenture relating to Sections 310
through 318, inclusive, of the Trust Indenture Act of 1939:

NOTE: This reconciliation and tie shall not, for any purpose, be deemed to be a part of the Indenture.

     INDENTURE, dated as of June 9, 2009, among Express Scripts, Inc., a corporation duly organized and existing under the laws of the State of Delaware (herein called the “ Company ”), having its principal executive office at One Express Way, St. Louis, Missouri 63121, any Guarantors (as defined herein) party hereto, and Union Bank, N.A., a national banking association, as Trustee (herein called the “ Trustee ”).

RECITALS OF THE COMPANY AND GUARANTORS

     The Company has duly authorized the execution and delivery of this Indenture to provide for the issuance from time to time of its unsecured debentures, notes or other evidences of indebtedness (herein called the “ Securities ”), to be issued in one or more series, which Securities may be guaranteed by each of the Guarantors, as provided in this Indenture.

     All things necessary to make this Indenture a valid agreement of the Company and any Guarantors, in accordance with its terms, have been done.

NOW, THEREFORE, THIS INDENTURE WITNESSETH:

     For and in consideration of the premises and the purchase of the Securities by the Holders thereof, it is mutually covenanted and agreed, for the equal and proportionate benefit of all Holders of the Securities or of series thereof appertaining, as follows:

ARTICLE ONE

DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

      Section 101. Definitions.

For all purposes of this Indenture and the Securities authenticated and delivered under this Indenture, except as otherwise expressly provided or unless the context otherwise requires:

     (1) the terms defined in this Article have the meanings assigned to them in this Article and include the plural as well as the singular;

     (2) all other terms used herein which are defined in the Trust Indenture Act, either directly or by reference therein, have the meanings assigned to them therein;

     (3) all accounting terms not otherwise defined herein have the meanings assigned to them in accordance with generally accepted accounting principles in the United States, and, except as otherwise herein expressly provided, the term “generally accepted accounting principles” with respect to any computation required or permitted hereunder shall mean such accounting principles as are generally accepted in the United States at the date of this instrument;

     (4) unless the context otherwise requires, any reference to an “Article” or a “Section” refers to an Article or a Section, as the case may be, of this Indenture;

     (5) the words “herein,” “hereof,” “hereunder” and other words of similar import refer to this Indenture or the Securities, as applicable, as a whole and not to any particular Article, Section or other subdivision; and

     (6) the term “including” means including without limitation.

     “ Act ,” when used with respect to any Holder, has the meaning specified in Section 104.

     “ Affiliate ” of any specified Person means any other Person directly or indirectly controlling or controlled by or under direct or indirect common control with such specified Person. For the purposes of this definition, “control” when used with respect to any specified Person means the power to direct the management and policies of such Person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise; and the terms “controlling” and “controlled” have meanings correlative to the foregoing.

     “ Authenticating Agent ” means any Person authorized by the Trustee pursuant to Section 614 to act on behalf of the Trustee to authenticate Securities of one or more series.

     “ Board of Directors ” means either the board of directors of the Company or any duly authorized committee empowered by that board to act with respect to this Indenture.

     “ Board Resolution ” means a copy of a resolution certified by the Secretary or an Assistant Secretary of the Company to have been duly adopted by the Board of Directors and to be in full force and effect on the date of such certification, and delivered to the Trustee.

     “ Business Day ,” means, with respect to any Place of Payment, means each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in that Place of Payment are authorized or obligated by law or executive order to close, except as may otherwise be provided in the form of Securities of any particular series pursuant to the provisions of this Indenture.

     “ Commission ” means the Securities and Exchange Commission, as from time to time constituted, created under the Exchange Act, or, if at any time after the execution of this Indenture such Commission is not existing and performing the duties now assigned to it under the Trust Indenture Act, then the body performing such duties at such time.

     “ Common Stock ” includes any stock of any class of the Company which has no preference in respect of dividends or of amounts payable in the event of any voluntary or involuntary liquidation, dissolution or winding-up of the Company and which is not subject to redemption by the Company; provided , however , subject to the provisions of Section 1409, shares issuable upon conversion of Securities shall include only shares of the class designated as Common Stock of the Company at the date of this Indenture or shares of any class or classes resulting from any reclassification or reclassifications thereof and which have no preference in respect of dividends or of amounts payable in the event of any voluntary or involuntary liquidation, dissolution or winding-up of the Company and which are not subject to redemption by the Company; provided , further , that if at any time there shall be more

than one such resulting class, the shares of each such class then so issuable shall be substantially in the proportion which the total number of shares of such class resulting from all such reclassifications bears to the total number of shares of all such classes resulting from all such reclassifications.

     “ Company ” means the corporation named as the “Company” in the first paragraph of this Indenture until a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Company” shall means such successor corporation.

     “ Company Request ” or “ Company Order ” means a written request or order signed in the name of the Company by (a) its Chairman of the Board of Directors, its Chief Executive Officer, its President or a Vice President, its Chief Financial Officer, its Treasurer or an Assistant Treasurer, and (b) its Secretary or an Assistant Secretary, and delivered to the Trustee.

     “ Constituent Person ” has the meaning specified in Section 1409.

     “ Corporate Trust Office ” means the principal corporate trust office of the Trustee, which office, at the date of execution of this Indenture, is located at 551 Madison Avenue, 11 ^th Floor, New York, NY 10022, Attention: Corporate Trust Department (Express Scripts Debt Securities), at which at any particular time its corporate trust business shall be administered.

     “ corporation ” means a corporation, association, company, limited liability company, joint-stock company or business trust.

     “ Covenant Defeasance ” has the meaning specified in Section 1303.

     “ Debt ” of any Person at any date means all indebtedness for borrowed money.

     “ Default ” means any event which is, or after notice or passage of time or both, would be, an Event of Default.

     “ Defaulted Interest ” has the meaning specified in Section 307.

     “ Defeasance ” has the meaning specified in Section 1302.

     “ Depositary ” means, with respect to Securities of any series issuable in whole or in part in the form of one or more Global Securities, a clearing agency registered under the Exchange Act that is designated to act as Depositary for such Securities as contemplated by Section 301, until a successor Depositary shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Depositary” shall mean or include each person who is then a Depositary hereunder, and if at any time there is more than one such Person, “Depositary” as used with respect to the Securities of any such series shall mean the Depositary with respect to the Securities of that series.

     “ Dollar ” or “ $ ” means a dollar or other equivalent unit in such coin or currency of the United States of America as at the time shall be legal tender for the payment of public and private debts.

     “ Event of Default ” unless otherwise specified in the supplemental indenture establishing series of Securities, has the meaning specified in Section 501.

     “ Exchange Act ” means the United States Securities Exchange Act of 1934 and the rules and regulations promulgated by the Commission thereunder and any statute successor thereto, in each case as amended from time to time.

     “ Expiration Date ” has the meaning specified in Section 104.

     “ Funding Guarantor ” has the meaning specified in Section 1505.

     “ Global Security ” means a Security that evidences all or part of the Securities of any series, which is executed by the Company and authenticated and delivered by the Trustee to the applicable Depositary for such series in accordance with Section 303, and bears the legend set forth in Section 204 (or such legend as may be specified as contemplated by Section 301 for such Securities).

     “ Guarantee ” has the meaning stated in Section 1501(2). The term “Guarantee” used as a verb has a corresponding meaning.

     “ Guarantors ” means any Subsidiary of the Company and any other Affiliate of the Company who may execute this Indenture, or a supplement hereto, for the purpose of providing a Guarantee of Securities pursuant to this Indenture until (a) a successor Person shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Guarantors” shall mean such successor Person or (b) such Person shall have been released from its Guarantee pursuant to the provisions of this Indenture.

     “ Holder ” means a Person in whose name a Security is registered in the Security Register.

     “ Indenture ” means this instrument as originally executed or as it may from time to time be supplemented or amended by one or more indentures supplemental hereto entered into pursuant to the applicable provisions hereof, including, for all purposes of this instrument and any such supplemental indenture, the provisions of the Trust Indenture Act that are deemed to be a part of and govern this instrument and any such supplemental indenture, respectively. The term “Indenture” shall also include the terms of particular series of Securities established as contemplated by Section 301; provided , however , that if at any time more than one Person is acting as Trustee under this Indenture due to the appointment of one or more separate Trustees for any one or more separate series of Securities, “Indenture” shall mean, with respect to such series of Securities for which any such Person is Trustee, this instrument as originally executed or as it may from time to time be supplemented or amended by one or more indentures supplemental hereto entered into pursuant to the applicable provisions hereof and shall include the terms of particular series of Securities for which such Person is Trustee established as contemplated by Section 301, exclusive, however, of any provisions or terms which relate solely to other series of Securities for which such Person is not Trustee, regardless of when such terms or provisions were adopted, and exclusive of any provisions or terms adopted by means of one or more indentures supplemental hereto executed and delivered after such person had become such Trustee, but to which such person, as such Trustee, was not a party; provided , further that in the event that this Indenture is supplemented or amended by one or more indentures supplemental hereto which are only

applicable to certain series of Securities, the term “Indenture” for a particular series of Securities shall only include the supplemental indentures applicable thereto.

     “ Interest Payment Date ,” when used with respect to any Security, means the Stated Maturity of an installment of interest on such Security.

     “ Investment Company Act ” means the Investment Company Act of 1940 and any statute successor thereto, in each case as amended from time to time.

     “ Maturity ,” when used with respect to any Security, means the date on which the principal of such Security becomes due and payable as therein or herein provided, whether at the Stated Maturity or by declaration of acceleration, call for redemption, repurchase at the option of the Holder or otherwise.

     “ Non-electing Share ” has the meaning specified in Section 1409.

     “ Notice of Default ” means a written notice of the kind specified in Section 501(4).

     “ Officer ” means the Chairman of the Board of Directors, the Chief Executive Officer, the President, any Vice President, the Chief Financial Officer, the Treasurer, any Assistant Treasurer, any Secretary or any Assistant Secretary.

     “ Officers’ Certificate ” means a certificate signed by two Officers of the Company, and delivered to the Trustee. One of the officers signing an Officers’ Certificate given pursuant to Section 1004 shall be the principal executive, financial or accounting officer of the Company.

     “ Opinion of Counsel ” means a written opinion of counsel, who may be counsel for, or an employee of, the Company, and who shall be reasonably acceptable to the Trustee.

     “ Original Issue Discount Security ” means any Security which provides for an amount less than the principal amount thereof to be due and payable upon a declaration of acceleration of the Maturity thereof pursuant to Section 502.

     “ Outstanding ,” when used with respect to Securities or Securities of any series, means, as of the date of determination, all such Securities theretofore authenticated and delivered under this Indenture, except:

     (1) Securities theretofore canceled by the Trustee or delivered to the Trustee for cancellation;

     (2) Securities for whose payment or redemption money in the necessary amount has been theretofore deposited with the Trustee or any Paying Agent (other than the Company) in trust or set aside and segregated in trust by the Company (if the Company shall act as its own Paying Agent) for the Holders of such Securities; provided that , if such Securities are to be redeemed, notice of such redemption has been duly given pursuant to this Indenture or provision therefor satisfactory to the Trustee has been made;

     (3) Securities as to which Defeasance has been effected pursuant to Section 1302; and

     (4) Securities which have been paid pursuant to Section 306 or in exchange for or in lieu of which other Securities have been authenticated and delivered pursuant to this Indenture, other than any such Securities in respect of which there shall have been presented to the Trustee proof satisfactory to it that such Securities are held by a bona fide purchaser in whose hands such Securities are valid obligations of the Company;

provided , however , that in determining whether the Holders of the requisite principal amount of the Outstanding Securities have given, made or taken any request, demand, authorization, direction, notice, consent, waiver or other action hereunder as of any date, (A) the principal amount of an Original Issue Discount Security which shall be deemed to be Outstanding shall be the amount of the principal thereof which would be due and payable as of such date upon acceleration of the Maturity thereof to such date pursuant to Section 502, (B) if, as of such date, the principal amount payable at the Stated Maturity of a Security is not determinable, the principal amount of such Security which shall be deemed to be Outstanding shall be the amount as specified or determined as contemplated by Section 301, (C) the principal amount of a Security denominated in one or more foreign currencies or currency units which shall be deemed to be Outstanding shall be the U.S. dollar equivalent, determined as of such date in the manner provided as contemplated by Section 301, of the principal amount of such Security (or, in the case of a Security described in Clause (A) or (B) above, of the amount determined as provided in such Clause), and (D) Securities owned by the Company or any other obligor upon the Securities or any Affiliate of the Company or of such other obligor shall be disregarded and deemed not to be Outstanding, except that, in determining whether the Trustee shall be protected in relying upon any such request, demand, authorization, direction, notice, consent, waiver or other action, only Securities which a responsible officer of the Trustee actually knows to be so owned shall be so disregarded. Securities so owned which have been pledged in good faith may be regarded as Outstanding if the pledgee establishes to the satisfaction of the Trustee the pledgee’s right so to act with respect to such Securities and that the pledgee is not the Company or any other obligor upon the Securities or any Affiliate of the Company or of such other obligor.

     “ Paying Agent ” means any Person authorized by the Company to pay the principal or premium, if any, or interest, if any, on any Securities on behalf of the Company, and shall initially be the Trustee.

     “ Person ” means any individual, corporation, limited liability company, partnership, joint venture, trust, unincorporated organization or government or any agency or political subdivision thereof or any other entity of any kind.

     “ Place of Payment ,” when used with respect to the Securities of any series, means the place or places where the principal of and any premium and interest on the Securities of that series are payable as specified in or as contemplated by Section 301.

     “ Predecessor Security ” of any particular Security means every previous Security evidencing all or a portion of the same debt as that evidenced by such particular Security, and, for the purposes of this definition, any Security authenticated and delivered under Section 306 in exchange for or in lieu of a mutilated, destroyed, lost or stolen Security shall be deemed to evidence the same debt as the mutilated, destroyed, lost or stolen Security.

     “ Record Date ” means any Regular Record Date or Special Record Date.

     “ Redemption Date ,” when used with respect to any Security to be redeemed, means the date fixed for such redemption by or pursuant to this Indenture.

     “ Redemption Price ,” when used with respect to any Security to be redeemed, means the price at which it is to be redeemed pursuant to this Indenture.

     “ Regular Record Date ” for the interest payable on any Interest Payment Date on the Securities of any series means the date specified for that purpose as contemplated by Section 301.

     “ Securities ” has the meaning stated in the first recital of this Indenture and more particularly means any securities authenticated and delivered under this Indenture.

     “ Securities Act ” means the Securities Act of 1933 and any statute successor thereto, in each case as amended from time to time.

     “ Security Register ” and “ Security Registrar ” have the respective meanings specified in Section 305.

     “ Significant Subsidiary ” with respect to any Person means any Subsidiary of such Person that constitutes a “significant subsidiary” within the meaning of Rule 1-02(w) of Regulation S-X promulgated under the Securities Act, as such regulation is in effect on the date of this Indenture.

     “ Special Record Date ” for the payment of any Defaulted Interest means a date fixed by the Trustee pursuant to Section 307.

     “ Stated Maturity ,” when used with respect to any Security or any installment of principal thereof or interest, if any, thereon, means the date specified in such Security as the fixed date on which the principal of such Security or such installment of principal or interest, if any, is due and payable.

     “ Subsidiary ” with respect to any Person means (i) any corporation, association or other business entity of which more than 50% of the total voting power of shares of capital stock or other equity interests entitled (without regard to the occurrence of any contingency) to vote in the election of directors, managers or trustees thereof is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of such Person (or a combination thereof), (ii) any partnership, limited liability company or similar pass-through entity the sole general partner or the managing general partner or managing member of which is such Person or a Subsidiary of such Person and (iii) any partnership, limited liability company or similar pass-through entity the only general partners, managing members or Persons, however designated in corresponding roles, of which are such Person or one or more Subsidiaries of such Person (or any combination thereof).

     “ Trust Indenture Act ” means the Trust Indenture Act of 1939 as in force at the date as of which this Indenture was executed, except as provided in Section 905; provided , however , that in the event the Trust Indenture Act of 1939 is amended after such date, “Trust Indenture Act” means, to the extent required by any such amendment, the Trust Indenture Act of 1939 as so amended.

     “ Trustee ” means the Person named as the “Trustee” in the first paragraph of this Indenture until a successor Trustee shall have become such pursuant to the applicable provisions of this Indenture, and thereafter “Trustee” shall mean or include each Person who is then a Trustee hereunder, and if at any time there is more than one such Person, “Trustee” as used with respect to the Securities of any series shall mean the Trustee with respect to Securities of that series.

     “ U.S. Government Obligation ” has the meaning specified in Section 1304.

     “ Vice President ,” when used with respect to the Company or the Trustee, means any vice president, whether or not designated by a number or a word or words added before or after the title “vice president.”

      Section 102. Compliance Certificates and Opinions.

     Upon any application or request by the Company to the Trustee to take any action under any provision of this Indenture, the Company shall furnish to the Trustee (1) an Officers’ Certificate stating that all conditions precedent, if any, provided for in this Indenture relating to the proposed action have been complied with and (2) an Opinion of Counsel stating that in the opinion of such counsel all such conditions precedent, if any, have been complied with.

     Every certificate or opinion with respect to compliance with a condition or covenant provided for in this Indenture shall include,

     (1) a statement that each individual signing such certificate or opinion has read such covenant or condition and the definitions herein relating thereto;

     (2) a brief statement as to the nature and scope of the examination or investigation upon which the statements or opinions contained in such certificate or opinion are based;

     (3) a statement that, in the opinion of each such individual, he or she has made such examination or investigation as is necessary to enable him or her to express an informed opinion as to whether or not there has been compliance with such covenant or condition; and

     (4) a statement as to whether, in the opinion of each such individual, there has been compliance with such condition or covenant.

      Section 103. Form of Documents Delivered to Trustee.

     In any case where several matters are required to be certified by, or covered by an opinion of, any specified Person, it is not necessary that all such matters be certified by, or covered by the opinion of, only one such Person, or that they be so certified or covered by only one document, but one such Person may certify or give an opinion with respect to some matters and one or more other such Persons as to other matters, and any such Person may certify or give an opinion as to such matters in one or several documents.

     Any certificate or opinion of an officer of the Company or any Guarantor may be based, insofar as it relates to legal matters, upon a certificate or opinion of, or representations by, counsel, unless such officer knows, or in the exercise of reasonable care should know, that the certificate or opinion or representations with respect to the matters upon which his or her certificate or opinion is based are erroneous. Any such certificate or Opinion of Counsel may be based, insofar as it relates to factual matters, upon a certificate or opinion of, or representations by, an officer or officers of the Company or any Guarantor, as applicable, stating that the information with respect to such factual matters is in the possession of the Company or any Guarantor, as the case may be, unless such counsel knows, or in the exercise of reasonable care should know, that the certificate or opinion or representations with respect to such matters are erroneous. Any such certificate or opinion of counsel may be based, insofar as it relates to accounting matters, upon a certificate or opinion of, or representations by, an accountant (who may be an employee of the Company) or firm of accountants, unless such counsel knows, or in the exercise of reasonable care should know, that the certificate or opinion or representations with respect to such matters are erroneous. Where any Person is required to make, give or execute two or more applications, requests, consents, certificates, statements, opinions or other instruments under this Indenture, they may, but need not, be consolidated and form one instrument.

      Section 104. Acts of Holders; Record Dates.

     Any request, demand, authorization, direction, notice, consent, waiver or other action provided or permitted by this Indenture to be given, made or taken by Holders may be embodied in and evidenced by one or more instruments of substantially similar tenor signed by such Holders in person or by an agent duly appointed in writing; and, except as herein otherwise expressly provided, such action shall become effective when such instrument or instruments are delivered to the Trustee and, where it is hereby expressly required, to the Company. The Trustee shall promptly deliver to the Company copies of all such instrument or instruments and records delivered to the Trustee. Such instrument or instruments (and the action embodied therein and evidenced thereby) are herein sometimes referred to as the “ Act ” of the Holders signing such instrument or instruments. Proof of execution of any such instrument or of a writing appointing any such agent shall be sufficient for any purpose of this Indenture and (subject to Section 601) conclusive in favor of the Trustee and the Company, if made in the manner provided in this Section.

     The fact and date of the execution by any Person of any such instrument or writing may be proved by the affidavit of a witness of such execution or by a certificate of a notary public or other officer authorized by law to take acknowledgments of deeds, certifying that the individual signing such instrument or writing acknowledged to him or her the execution thereof. Where such execution is by a signer acting in a capacity other than his or her individual capacity, such certificate or affidavit shall also constitute sufficient proof of his or her authority. The fact and date of the execution of any such instrument or writing, or the authority of the Person executing the same, may also be proved in any other manner which the Trustee deems sufficient.

     The ownership of Securities shall be proved by the Security Register.

     Any request, demand, authorization, direction, notice, consent, waiver or other Act of the Holder of any Security shall bind every future Holder of the same Security and the Holder of every Security issued upon the registration of transfer thereof or in exchange therefor or in lieu thereof in respect of anything done, omitted or suffered to be done by the Trustee or the Company in reliance thereon, whether or not notation of such action is made upon such Security.

     The Company may, in the circumstances permitted by the Trust Indenture Act, set any day as a record date for the purpose of determining the Holders of Outstanding Securities of any series entitled to give, make or take any request, demand, authorization, direction, vote, notice, consent, waiver or other action provided or permitted by this Indenture to be given, made or taken by Holders of Securities of such series; provided that the Company may not set

a record date for, and the provisions of this paragraph shall not apply with respect to, the giving or making of any notice, declaration, request or direction referred to in the next paragraph. If any record date is set pursuant to this paragraph, the Holders of Outstanding Securities of the relevant series on such record date, and no other Holders, shall be entitled to take the relevant action, whether or not such Holders remain Holders after such record date; provided further that no such action shall be effective hereunder unless taken on or prior to the applicable Expiration Date by Holders of the requisite principal amount of Outstanding Securities of such series on such record date. Nothing in this paragraph shall be construed to prevent the Company from setting a new record date for any action for which a record date has previously been set pursuant to this paragraph (whereupon the record date previously set shall automatically and with no action by any Person be canceled and of no effect), and nothing in this paragraph shall be construed to render ineffective any action taken by Holders of the requisite principal amount of Outstanding Securities of the relevant series on the date such action is taken. Promptly after any record date is set pursuant to this paragraph, the Company, at its own expense, shall cause notice of such record date, the proposed action by Holders and the applicable Expiration Date to be given to the Trustee in writing and to each Holder of Securities of the relevant series in the manner set forth in Section 106.

     The Trustee may set any day as a record date for the purpose of determining the Holders of Outstanding Securities of any series entitled to join in the giving or making of (i) any Notice of Default, (ii) any declaration of acceleration referred to in Section 502, (iii) any request to institute proceedings referred to in Section 507(2) or (iv) any direction referred to in Section 512, in each case with respect to Securities of such series. If any record date is set pursuant to this paragraph, the Holders of Outstanding Securities of such series on such record date, and no other Holders, shall be entitled to join in such notice, declaration, request or direction, whether or not such Holders remain Holders after such record date; provided that no such action shall be effective hereunder unless taken on or prior to the applicable Expiration Date by Holders of the requisite principal amount of Outstanding Securities of such series on such record date. Nothing in this paragraph shall be construed to prevent the Trustee from setting a new record date for any action for which a record date has previously been set pursuant to this paragraph (whereupon the record date previously set shall automatically and with no action by any Person be canceled and of no effect), and nothing in this paragraph shall be construed to render ineffective any action taken by Holders of the requisite principal amount of Outstanding Securities of the relevant series on the date such action is taken. Promptly after any record date is set pursuant to this paragraph, the Trustee, at the Company’s expense, shall cause notice of such record date, the proposed action by Holders and the applicable Expiration Date to be given to the Company in writing and to each Holder of Securities of the relevant series in the manner set forth in Section 106.

     With respect to any record date set pursuant to this Section, the party hereto which sets such record dates may designate any day as the “ Expiration Date ” and from time to time may change the Expiration Date to any earlier or later day; provided that no such change shall be effective unless notice of the proposed new Expiration Date is given to the other party hereto in writing, and to each Holder of Securities of the relevant series in the manner set forth in Section 106, on or prior to the existing Expiration Date. If an Expiration Date is not designated with respect to any record date set pursuant to this Section, the party hereto which set such record date shall be deemed to have initially designated the 180th day after such record date as the Expiration Date with respect thereto, subject to its right to change the Expiration Date as provided in this paragraph. Notwithstanding the foregoing, no Expiration Date shall be later than the 180th day after the applicable record date.

     Without limiting the foregoing, a Holder entitled hereunder to take any action hereunder with regard to any particular Security may do so with regard to all or any part of the principal amount of such Security or by one or more duly appointed agents each of which may do so pursuant to such appointment with regard to all or any part of such principal amount.

      Section 105. Notices, Etc., to Trustee and Company.

     Any request, demand, authorization, direction, notice, consent, waiver or Act of Holders or other document provided or permitted by this Indenture to be made upon, given or furnished to, or filed with,

     (1) the Trustee by any Holder or by the Company shall be sufficient for every purpose hereunder if made, given, furnished or filed in writing (or by facsimile transmission ((646)-452-2000); provided that oral confirmation of receipt shall have been received) to or with the Trustee at its Corporate Trust Office, or

     (2) the Company by the Trustee or by any Holder shall be sufficient for every purpose hereunder (unless otherwise herein expressly provided) if in writing and mailed, first-class postage prepaid, to the Company addressed to it at the address of the Company’s principal office specified in the first paragraph of this instrument or at any other address previously furnished in writing to the Trustee by the Company, Attention: Chief Financial Officer, with a copy to the Secretary; provided that such notice shall not be deemed to be given until received by the Company.

      Section 106. Notice to Holders; Waiver.

     Where this Indenture provides for notice to Holders of any event, such notice shall be sufficiently given (unless otherwise herein expressly provided) if in writing and mailed, first-class postage prepaid, to each Holder affected by such event, at its address as it appears in the Security Register, not later than the latest date (if any), and not earlier than the earliest date (if any), prescribed for the giving of such notice. In any case where notice to Holders is given by mail, neither the failure to mail such notice, nor any defect in any notice so mailed, to any particular Holder shall affect the sufficiency of such notice with respect to other Holders. Where this Indenture provides for notice in any manner, such notice may be waived in writing by the Person entitled to receive such notice, either before or after the event, and such waiver shall be the equivalent of such notice. Waivers of notice by Holders shall be filed with the Trustee, but such filing shall not be a condition precedent to the validity of any action taken in reliance upon such waiver.

     In case by reason of the suspension of regular mail service or by reason of any other cause it shall be impracticable to give such notice by mail, then such notification as shall be made with the approval of the Trustee shall constitute a sufficient notification for every purpose hereunder.

      Section 107. Conflict with Trust Indenture Act.

     If any provision hereof limits, qualifies or conflicts with a provision of the Trust Indenture Act which is required under the Trust Indenture Act to be a part of and govern this Indenture, the latter provision shall control. If any provision of this Indenture modifies or excludes any provision of the Trust Indenture Act which may be so modified or excluded, the latter provision shall be deemed to apply to this Indenture as so modified or to be excluded, as the case may be.

      Section 108. Effect of Headings and Table of Contents.

     The Article and Section headings herein and the Table of Contents are for convenience only and shall not affect the construction hereof.

      Section 109. Successors and Assigns.

     All covenants and agreements in this Indenture by each of the Company and the Guarantors shall bind its successors and assigns, whether so expressed or not.

      Section 110. Separability Clause.

     In case any provision in this Indenture or in the Securities shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.

      Section 111. Benefits of Indenture.

     Nothing in this Indenture or in the Securities, express or implied, shall give to any Person, other than the parties hereto and their successors hereunder and the Holders, any benefit or any legal or equitable right, remedy or claim under this Indenture.

      Section 112. Governing Law; Waiver of Jury Trial

      THIS INDENTURE AND THE SECURITIES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICTS OF LAWS PRINCIPLES THEREOF. EACH OF THE COMPANY AND THE TRUSTEE HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS INDENTURE, THE SECURITIES OR THE TRANSACTION CONTEMPLATED HEREBY.

      Section 113. Legal Holidays.

     In any case where any Interest Payment Date, Redemption Date or Stated Maturity of any Security or the last date on which a Holder has the right to convert a Security at a particular conversion price shall not be a Business Day at any Place of Payment, then (notwithstanding any other provision of this Indenture or of the Securities (other than a provision of any Security which specifically states that such provision shall apply in lieu of this Section)) payment of interest or principal (and premium, if any) or, if applicable to a particular series of Securities, conversion need not be made at such Place of Payment on such date, but may be made on the next succeeding Business Day at such Place of Payment with the same force and effect as if made on the Interest Payment Date or Redemption Date, at the Stated Maturity or on such last day for conversion, as the case may be.

      Section 114. Indenture and Securities Solely Corporate Obligations.

     None of the Company’s or any Guarantor’s past, present or future directors, officers, employees or shareholders, as such, shall have any liability for any of the Company’s or any Guarantor’s obligations under this Indenture or the Securities or for any claim based on, or in respect or by reason of, such obligations or their creation. By accepting a Security, each holder waives and releases all such liability. This waiver and release is part of the consideration for the issuance of the Securities.

      Section 115. Indenture May be Executed in Counterparts.

     This Indenture may be executed in any number of counterparts, each of which so executed shall be deemed to be an original, but all such counterparts shall together constitute but one and the same instrument. The exchange of copies of this Indenture and of signature pages by facsimile or PDF transmission shall constitute effective execution and delivery of this Indenture as to the parties hereto and may be used in lieu of the original Indenture for all purposes. Signatures of the parties hereto transmitted by facsimile or PDF shall be deemed to be their original signatures for all purposes.

      Section 116. Acceptance of Trust.

     Union Bank, N.A., the Trustee named herein, hereby accepts the trusts in this Indenture declared and provided, upon the terms and conditions set forth herein.

      Section 117. Force Majeure

     In no event shall the Trustee be responsible or liable for any failure or delay in the performance of its obligations hereunder arising out of or caused by, directly or indirectly, forces beyond its control, including, without limitation, strikes, work stoppages, accidents, acts of war or terrorism, civil or military disturbances, nuclear or natural catastrophes or acts of God, and interruptions, loss or malfunctions of utilities, communications or computer (software and hardware) services; it being understood that the Trustee shall use reasonable efforts which are consistent with accepted practices in the banking industry to resume performance as soon as practicable under the circumstances.

      Section 118. U.S.A. Patriot Act

     The parties hereto acknowledge that in accordance with Section 326 of the U.S.A. Patriot Act, the Trustee, like all financial institutions and in order to help fight the funding of terrorism and money laundering, is required to obtain, verify, and record information that identifies each person or legal entity that establishes a relationship or opens an account with the Trustee. The parties to this Indenture agree that they will provide the Trustee with such information as it may request in order for the Trustee to satisfy the requirements of the U.S.A. Patriot Act.

ARTICLE TWO

SECURITY FORMS

      Section 201. Forms Generally.

     The Securities of each series shall be in substantially the form set forth in this Article, or in such other form as shall be established by or pursuant to a Board Resolution or in one or more indentures supplemental hereto, in each case with such appropriate insertions, omissions, substitutions and other variations as are required or permitted by this Indenture, and may have such letters, numbers or other marks of identification and such legends or endorsements placed thereon as may be required to comply with the rules of any securities exchange or Depositary therefor or as may, consistently herewith, be determined by the officers executing such Securities, as evidenced by their execution thereof. If the form of Securities of any series is established by action taken pursuant to a Board

Resolution, a copy of an appropriate record of such action shall be certified by the Secretary or an Assistant Secretary of the Company and delivered to the Trustee at or prior to the delivery of the Company Order contemplated by Section 303 for the authentication and delivery of such Securities. Any such Board Resolution or record of such action shall have attached thereto a true and correct copy of the form of Security referred to therein approved by or pursuant to such Board Resolution.

     The definitive Securities shall be printed, lithographed or engraved on steel engraved borders or may be produced in any other manner, all as determined by the officers executing such Securities, as evidenced by their execution of such Securities.

      Section 202. Form of Face of Security.

[Insert any legend required by the Internal Revenue Code and the regulations thereunder.]

EXPRESS SCRIPTS, INC.

     Express Scripts, Inc., a corporation duly organized and existing under the laws of Delaware (herein called the “ Company ,” which term includes any successor Person under the Indenture hereinafter referred to), for value received, hereby promises to pay to                      , or registered assigns, the principal sum of                      Dollars on                      [if the Security is to bear interest prior to Maturity, insert — , and to pay interest thereon from                      or from the most recent Interest Payment Date to which interest has been paid or duly provided for to, but excluding the next Interest Payment Date, [semi-annually on                      and                      ] in each year, commencing                      , at the rate of ___% per annum, until the principal hereof is paid or made available for payment [if applicable, insert — ; provided that any principal and premium, and any such installment of interest, which is overdue shall bear interest at the rate of [___%] per annum (to the extent that the payment of such interest shall be legally enforceable), from the dates such amounts are due until they are paid or made available for payment, and such interest shall be payable on demand]. The interest so payable, and punctually paid or duly provided for, on any Interest Payment Date will, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest, which shall be the                      or                      (whether or not a Business Day), as the case may be, next preceding such Interest Payment Date. Any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof shall be given to Holders of Securities of this series not fewer than 10 days prior to such Special Record Date, or be paid at any time in any other lawful manner not inconsistent with the requirements of any securities exchange on which the Securities of this series may be listed, and upon such notice as may be required by such exchange, all as more fully provided in said Indenture. Interest on the Security shall be computed on the basis of a 360 day year of twelve 30 day months.]

      [If the Security is not to bear interest prior to Maturity, insert — The principal of this Security shall not bear interest except in the case of a default in payment of principal upon acceleration, upon redemption or at Stated Maturity and in such case the overdue principal and any overdue premium shall bear interest at the rate of ___% per annum (to the extent that the payment of such interest shall be legally enforceable), from the dates such amounts are due until they are paid or made available for payment. Interest on any overdue principal or premium shall be payable on demand. Any such interest on overdue principal or premium which is not paid on demand shall

bear interest at the rate of ___% per annum (to the extent that the payment of such interest on interest shall be legally enforceable), from the date of such demand until the amount so demanded is paid or made available for payment. Interest on any overdue interest shall be payable on demand.]

     Payment of the principal of (and premium, if any) and [if applicable, insert — any such] interest on this Security will be made at the office or agency of the Company maintained for that purpose in                      , [if applicable, insert — which shall initially be the designated corporate trust office of the Trustee], in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts [if applicable, insert — ; provided , however , that at the option of the Company payment of interest may be made by check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register].

     Reference is hereby made to the further provisions of this Security set forth on the reverse hereof, which further provisions shall for all purposes have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been executed by the Trustee referred to on the reverse hereof by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed.

      Section 203. Form of Reverse of Security.

     This Security is one of a duly authorized issue of securities of the Company (herein called the “ Securities ”), issued and to be issued in one or more series under an Indenture, dated as of                      , 2009 (herein called the “ Indenture ,” which term shall have the meaning assigned to it in such instrument), among the Company, any Guarantors party thereto and Union Bank, N.A., as Trustee (herein called the “ Trustee ,” which term includes any successor trustee under the Indenture), and reference is hereby made to the Indenture and all indentures supplemental thereto applicable to this Security for a statement of the respective rights, limitations of rights, duties and immunities thereunder of the Company, the Guarantors, the Trustee and the Holders of the Securities and of the terms upon which the Securities are, and are to be, authenticated and delivered. This Security is one of the series designated on the face hereof [if applicable, insert — , limited in aggregate principal amount to $                      ].

      [If applicable, insert — The Securities of this series are subject to redemption upon not fewer than 30 days’ nor more than 60 days’ notice by mail, [if applicable, insert — (1) on                      in any year commencing with the year                      and ending with the year                      through operation of the sinking fund for this series at a Redemption Price equal to 100% of the principal amount, and (2)] at any time [if applicable, insert — on or after                      , 20___], in whole or in part, at the election of the Company, at the following Redemption Prices (expressed as percentages of the principal amount): If redeemed [if applicable, insert — on or before                      ,                      %, and if redeemed] during the 12-month period beginning                      of the years indicated, and thereafter at a Redemption Price equal to                      % of the principal amount, together in the case of any such redemption [if applicable, insert — (whether through operation of the sinking fund or otherwise)] with accrued interest to the Redemption Date, but interest installments whose Stated Maturity is on or prior to such Redemption Date will be payable to the Holders of such Securities, or one or more Predecessor Securities, of record at the close of business on the relevant Record Dates referred to on the face hereof, all as provided in the Indenture.]

      [If applicable, insert — The Securities of this series are subject to redemption upon not fewer than 30 days’ nor more than 60 days’ notice by mail, (1) on                      in any year commencing with the year                      and ending with the year                      through operation of the sinking fund for this series at the Redemption Prices for redemption through operation of the sinking fund (expressed as percentages of the principal amount) set forth in the table below, and (2) at any time [if applicable, insert — on or after                      ], as a whole or in part, at the election of the Company, at the Redemption Prices for redemption otherwise than through operation of the sinking fund (expressed as percentages of the principal amount) set forth in the table below: If redeemed during the 12-month period beginning                      of the years indicated,

and thereafter at a Redemption Price equal to ___% of the principal amount, together in the case of any such redemption (whether through operation of the sinking fund or otherwise) with accrued interest to the Redemption Date, but interest installments whose Stated Maturity is on or prior to such Redemption Date will be payable to the Holders of such Securities, or one or more Predecessor Securities, of record at the close of business on the relevant Record Dates referred to on the face hereof, all as provided in the Indenture.]

      [If applicable, insert — Notwithstanding the foregoing, the Company may not, prior to                      , redeem any Securities of this series as contemplated by [if applicable, insert — Clause (2) of] the preceding paragraph as a part of, or in anticipation of, any refunding operation by the application, directly or indirectly, of moneys borrowed having an interest cost to the Company (calculated in accordance with generally accepted financial practice) of less than ___% per annum.]

      [If applicable, insert — The sinking fund for this series provides for the redemption on                      , in each year beginning with the year                      and ending with the year                      of [if applicable, insert — not less than $                      (“ mandatory sinking fund ”) and not more than] $                      aggregate principal amount of Securities of this series. Securities of this series acquired or redeemed by the Company otherwise than through [if applicable, insert — mandatory] sinking fund payments may be credited against subsequent [if applicable, insert — mandatory] sinking fund payments otherwise required to be made [if applicable, insert — , in the inverse order in which they become due].]

      [If the Security is subject to redemption of any kind, insert — In the event of redemption of this Security in part only, a new Security or Securities of this series and of like tenor for the unredeemed portion hereof will be issued in the name of the Holder hereof upon the cancellation hereof.]

      [If applicable, insert — The Indenture contains provisions for defeasance at any time of [the entire indebtedness of this Security] [or] [certain restrictive covenants and Events of Default with respect to this Security] [, in each case] upon compliance with certain conditions set forth in the Indenture.]

      [If the Security is convertible into Common Stock of the Company, insert — Subject to the provisions of the Indenture, the Holder of this Security is entitled, at its option, at any time on or prior to Maturity (except that, in case this Security or any portion hereof shall be called for redemption, such right shall terminate with respect to this Security or portion hereof, as the case may be, so called for redemption at the close of business on the first Business Day next preceding the date fixed for redemption as provided in the Indenture unless the Company defaults in making the payment due upon redemption), to convert the principal amount of this Security (or any portion hereof which is $1,000 or an integral multiple thereof), into fully paid and non-assessable shares (calculated as to each conversion to the nearest 1/100th of a share) of the Common Stock of the Company, as said shares shall be constituted at the date of conversion, at the conversion price of $                      principal amount of Securities for each share of Common Stock, or at the adjusted conversion price in effect at the date of conversion determined as provided in the Indenture, upon surrender of this Security, together with the conversion notice hereon duly executed, to the Company at the designated office or agency of the Company in                      , accompanied (if so required by the Company) by instruments of transfer, in form satisfactory to the Company and to the Trustee, duly executed by the Holder or by its duly authorized attorney in writing. Such surrender shall, if made during any period beginning at the close of business on a Regular Record Date and ending at the opening of business on the Interest Payment Date next following such Regular Record Date (unless this Security or the portion being converted shall have been called for redemption on a Redemption Date during the period beginning at the close of business on a Regular Record Date and ending at the opening of business on the first Business Day after the next succeeding Interest Payment Date, or if such Interest Payment Date is not a Business Day, the second such Business Day), also be accompanied by payment in funds acceptable to the Company of an amount equal to the interest payable on such Interest Payment Date on the principal amount of this Security then being converted. Subject to the aforesaid requirement for payment and, in the case of a conversion after the Regular Record Date next preceding any Interest Payment Date and on or before such Interest Payment Date, to the right of the Holder of this Security (or any Predecessor Security) of record at such Regular Record Date to receive an installment of interest (with certain exceptions provided in the Indenture), no adjustment is to be made on conversion for interest accrued hereon or for dividends on shares of Common Stock issued on conversion. The Company is not required to issue fractional shares upon any such conversion, but shall make adjustment therefor in cash on the basis of the current market value of such fractional interest as provided in the Indenture. The conversion price is subject to adjustment as provided in the Indenture. In addition, the Indenture provides that in case of certain consolidations or mergers to which the Company is a party or the sale of substantially all of the assets of the Company, the Indenture shall be amended,

without the consent of any Holders of Securities, so that this Security, if then outstanding, will be convertible thereafter, during the period this Security shall be convertible as specified above, only into the kind and amount of securities, cash and other property receivable upon the consolidation, merger or sale by a holder of the number of shares of Common Stock into which this Security might have been converted immediately prior to such consolidation, merger or sale (assuming such holder of Common Stock failed to exercise any rights of election and received per share the kind and amount received per share by a plurality of non-electing shares). In the event of conversion of this Security in part only, a new Security or Securities for the unconverted portion hereof shall be issued in the name of the Holder hereof upon the cancellation hereof.]

      [If the Security is convertible into other securities of the Company, provides for adjustments to the conversion rate or provides for other means to settle conversion, specify the conversion features.]

      [If the Security is not an Original Issue Discount Security, insert — If an Event of Default with respect to Securities of this series shall occur and be continuing, the principal of the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture.]

      [If the Security is an Original Issue Discount Security, insert — If an Event of Default with respect to Securities of this series shall occur and be continuing, an amount of principal of the Securities of this series may be declared due and payable in the manner and with the effect provided in the Indenture. Such amount shall be equal to — insert formula for determining the amount . Upon payment (i) of the amount of principal so declared due and payable and (ii) of interest on any overdue principal, premium and interest (in each case to the extent that the payment of such interest shall be legally enforceable), all of the Company’s obligations in respect of the payment of the principal of and premium and interest, if any, on the Securities of this series shall terminate.]

     The Indenture permits, with certain exceptions as therein provided, the amendment thereof and the modification of the rights and obligations of the Company and the rights of the Holders of the Securities of each series to be affected under the Indenture at any time by the Company and the Trustee with the consent of the Holders of at least a majority in principal amount of the Securities at the time Outstanding of each series to be affected. The Indenture also contains provisions permitting the Holders of specified percentages in principal amount of the Securities of each series at the time Outstanding, on behalf of the Holders of all Securities of such series, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange herefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security.

     As provided in and subject to the provisions of the Indenture, the Holder of this Security shall not have the right to institute any proceeding with respect to the Indenture or for the appointment of a receiver or trustee or for any other remedy thereunder, unless such Holder shall have previously given the Trustee written notice of a continuing Event of Default with respect to the Securities of this series, the Holders of not less than 25% in principal amount of the Securities of this series at the time Outstanding shall have made written request to the Trustee to institute proceedings in respect of such Event of Default as Trustee and offered the Trustee indemnity reasonably satisfactory to it, and the Trustee shall not have received from the Holders of a majority in principal amount of Securities of this series at the time Outstanding a direction inconsistent with such request, and shall have failed to institute any such proceeding, for 60 days after receipt of such notice, request and offer of indemnity. The foregoing shall not apply to any suit instituted by the Holder of this Security for the enforcement of any payment of principal hereof or any premium or interest hereon on or after the respective due dates expressed herein.

     No reference herein to the Indenture and no provision of this Security or of the Indenture shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of and any premium and interest on this Security at the times, place and rate, and in the coin or currency, herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security Register, upon surrender of this Security for registration of transfer at the office or agency of the Company in any place where the principal of and any premium and interest on this Security are payable, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed by, the Holder hereof or its attorney duly authorized in writing, and thereupon one or more new Securities of this series and of like tenor, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees.

     The Securities of this series are issuable only in registered form without coupons in denominations of $                      and any integral multiple thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of this series and of like tenor of a different authorized denomination, as requested by the Holder surrendering the same.

     No service charge shall be made for any such registration of transfer or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the owner hereof for all purposes, whether or not this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary.

     This Security shall be deemed to be a contract made under the laws of the State of New York, and for all purposes shall be construed in accordance with and governed by the laws of said State, without regard to conflict of laws principles thereof.

     All terms used in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture.

      Section 204. Form of Legend for Global Securities.

     Unless otherwise specified as contemplated by Section 301 for the Securities evidenced thereby, every Global Security authenticated and delivered hereunder shall bear a legend in substantially the following form:

      THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF. THIS SECURITY MAY NOT BE EXCHANGED IN WHOLE OR IN PART FOR A SECURITY REGISTERED, AND NO TRANSFER OF THIS SECURITY IN WHOLE OR IN PART MAY BE REGISTERED, IN THE NAME OF ANY PERSON OTHER THAN SUCH DEPOSITARY OR A NOMINEE THEREOF, EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE.

      Section 205. Form of Trustee’s Certificate of Authentication.

     The Trustee’s certificates of authentication shall be in substantially the following form:

     This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture.

Dated:

      Section 206. Form of Conversion Notice.

     Conversion notices shall be in substantially the following form, with such changes as are appropriate for the applicable series of Securities:

     To Express Scripts, Inc.:

     The undersigned owner of this Security hereby irrevocably exercises the option to convert this Security, or portion hereof (which is $1,000 or an integral multiple thereof) below designated, in accordance with the terms of the Indenture referred to in this Security, and directs that any shares issuable and deliverable upon the conversion, together with any check in payment for fractional shares and any Securities representing any unconverted principal amount hereof, be issued and delivered to the registered holder hereof unless a different name has been indicated below. If this Notice is being delivered on a date after the close of business on a Regular Record Date and prior to the opening of business on the related Interest Payment Date (unless this Security or the portion thereof being converted has been called for redemption on a Redemption Date during the period beginning at the close of business on a Regular Record Date and ending at the opening of business on the first Business Day after the next succeeding Interest Payment Date, or if such Interest Payment Date is not a Business Day, the second such Business Day), this Notice is accompanied by payment, in funds acceptable to the Company, of an amount equal to the interest payable on such Interest Payment Date of the principal of this Security to be converted. If shares are to be issued in the name of a person other than the undersigned, the undersigned will pay all transfer taxes payable with respect to this option exercise, including such issuance. Any amount required to be paid by the undersigned on account of interest accompanies this Security.

Principal Amount to be Converted (in an integral multiple of $1,000, if less than all)

U.S. $                     
Dated:                                         

Fill in for registration of shares of Common Stock and Security if to be issued otherwise than to the registered Holder.

[The above conversion notice is to be modified, as appropriate, for conversion into other securities or property of the Company.]

ARTICLE THREE

THE SECURITIES

      Section 301. Amount Unlimited; Issuable in Series.

     The aggregate principal amount of Securities which may be authenticated and delivered under this Indenture is unlimited.

     The Securities may be issued in one or more series. There shall be established in or pursuant to a Board Resolution and, subject to Section 303, set forth, or determined in the manner provided, in an Officers’ Certificate, or established in one or more indentures supplemental hereto, prior to the issuance of Securities of any series, any or all of the following:

     (1) the title of the Securities of the series (which shall distinguish the Securities of the series from Securities of any other series);

     (2) any limit upon the aggregate principal amount of the Securities of the series which may be authenticated and delivered under this Indenture (except for Securities authenticated and delivered upon registration of transfer of, or in exchange for, or in lieu of, other Securities of the series pursuant to Section 304, 305, 306, 906 or 1107 and except for any Securities which, pursuant to Section 303, are deemed never to have been authenticated and delivered hereunder);

     (3) the price or prices at which the Securities of such series will be offered by the Company (such price or prices to be expressed as a percentage of the principal amount of the Securities of such series);

     (4) the Person to whom any interest on a Security of the series shall be payable, if other than the Person in whose name that Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest;

     (5) the date or dates on which the principal of any Securities of the series is payable;

     (6) the rate or rates at which any Securities of the series shall bear interest, if any, or the method of determining the rate or rates, the date or dates from which any such interest shall accrue, the Interest Payment Dates on which any such interest shall be payable or the method of determining such dates and the Regular Record Date for any such interest payable on any Interest Payment Date;

     (7) the rate or rates of interest, if any, payable on overdue installments of principal of, or any premium or interest on the Securities of such series, and the basis upon which interest shall be calculated if other than that of a 360-day year comprised of twelve 30-day months;

     (8) the place or places where the principal of and any premium, if any, and interest on any Securities of the series shall be payable;

     (9) the period or periods within which, the price or prices at which and the terms and conditions upon which any Securities of the series may be redeemed, in whole or in part, at the option of the Company or otherwise and, if other than by a Board Resolution, the manner in which any election by the Company to redeem the Securities shall be evidenced;

     (10) the obligation, if any, of the Company to redeem or purchase any Securities of the series pursuant to any sinking fund or analogous provisions or otherwise at the option of the Holder thereof and the period or periods within which, the price or prices at which and the terms and conditions upon which any Securities of the series shall be redeemed or purchased, in whole or in part, pursuant to such obligation;

     (11) if other than denominations of $2,000 and any integral multiples of $1,000 in excess thereof, the denominations in which any Securities of the series shall be issuable;

     (12) if the amount of principal of or any premium or interest on any Securities of the series may be determined with reference to an index or pursuant to a formula, the manner in which such amounts shall be determined;

     (13) if other than the currency of the United States of America, the currency, currencies or currency units in which the principal of or any premium or interest on any Securities of the series shall be payable and the manner of determining the equivalent thereof in the currency of the United States of America for any purpose, including for purposes of the definition of “Outstanding” in Section 101;

     (14) if the principal of or any premium or interest on any Securities of the series is to be payable, at the election of the Company or the Holder thereof, in one or more currencies or currency units other than that or those in which such Securities are stated to be payable, the currency, currencies or currency units in which the principal of or any premium or interest on such Securities as to which such election is made shall be payable, the periods within which and the terms and conditions upon which such election is to be made and the amount so payable (or the manner in which such amount shall be determined);

     (15) if other than the entire principal amount thereof, the portion of the principal amount of any Securities of the series which shall be payable upon declaration of acceleration of the Maturity thereof pursuant to Section 502;

     (16) if the principal amount payable at the Stated Maturity of any Securities of the series will not be determinable as of any one or more dates prior to the Stated Maturity, the amount which shall be deemed to be the principal amount of such Securities as of any such date for any purpose thereunder or hereunder, including the principal amount thereof which shall be due and payable upon any Maturity other than the Stated Maturity or which shall be deemed to be Outstanding as of any date prior to the Stated Maturity (or, in any such case, the manner in which such amount deemed to be the principal amount shall be determined);

     (17) if applicable, that the Securities of the series, in whole or any specified part, shall be defeasible pursuant to Section 1302 or Section 1303 or both such Sections and, if other than by a Board

Resolution, the manner in which any election by the Company to defease such Securities shall be evidenced and any changes or additions to the provisions provided in Article Thirteen of this Indenture and related definitions and provisions dealing with defeasance, including the addition of additional covenants that may be subject to the Company’s Covenant Defeasance option;

     (18) if applicable, the terms of any right to convert Securities of the series into, or exchange securities for, shares of Common Stock of the Company or other securities or property or cash in lieu of such Common Stock or other securities or property, or any combination thereof, and any corresponding changes to the provisions of this Indenture as then in effect;

     (19) if applicable, that any Securities of the series shall be issuable in whole or in part in the form of one or more Global Securities and, in such case, the respective Depositaries for such Global Securities, the form of any legend or legends which shall be borne by any such Global Security in addition to or in lieu of that set forth in Section 204 and any circumstances in addition to or in lieu of those set forth in Clause (2) of the last paragraph of Section 305 in which any such Global Security may be exchanged in whole or in part for Securities registered, and any transfer of such Global Security in whole or in part may be registered, in the name or names of Persons other than the Depositary for such Global Security or a nominee thereof;

     (20) any addition to or change in the Events of Default which applies to any Securities of the series and any change in the right of the Trustee or the requisite Holders of such Securities to declare the principal amount thereof due and payable pursuant to Section 502;

     (21) any Authenticating Agents, Paying Agents or Security Registrars;

     (22) whether Securities of the series are entitled to any benefits of any Guarantee of any Guarantors pursuant to this Indenture;

     (23) the terms, if any, of the transfer, mortgage, pledge or assignment as security for the Securities of the series of any properties, assets, moneys, proceeds, securities or other collateral, including whether certain provisions of the Trust Indenture Act are applicable and any corresponding changes to provisions of this Indenture as then in effect;

     (24) any addition to or change in the covenants set forth in Article Ten which applies to Securities of the series; and

     (25) any other terms of the series (which terms shall not be inconsistent with the provisions of this Indenture, except as permitted by Section 901(5)).

     All Securities of any one series shall be substantially identical except as to denomination and except as may otherwise be provided in or pursuant to the Board Resolution referred to above and (subject to Section 303) set forth, or determined in the manner provided, in the Officers’ Certificate referred to above or in any such indenture supplemental hereto. All Securities of any one series need not be issued at the same time and, unless otherwise provided, a series may be reopened for issuances of additional Securities of such series.

     If any of the terms of the series are established by action taken pursuant to a Board Resolution, a copy of an appropriate record of such action shall be certified by the Secretary or an Assistant Secretary of the Company and delivered to the Trustee at or prior to the delivery of the Officers’ Certificate setting forth the terms of the series.

      Section 302. Denominations.

     The Securities of each series shall be issuable only in registered form without coupons and only in such denominations as shall be specified as contemplated by Section 301. In the absence of any such specified denomination with respect to the Securities of any series, the Securities of such series shall be issuable in minimum denominations of $2,000 and any integral multiple of $1,000 in excess thereof.

      Section 303. Execution, Authentication, Delivery and Dating.

     The Securities shall be executed on behalf of the Company by its Chairman of the Board of Directors, its principal financial officer, its Chief Executive Officer, its President or one of its Vice Presidents, its Treasurer or its Assistant Treasurer, attested by its Secretary or one of its Assistant Secretaries. The signature of any of these officers on the Securities may be manual or facsimile.

     The Guarantee endorsed on any Securities shall be executed on behalf of the Guarantor by its Chairman of the Board of Directors, its principal financial officer, its Chief Executive Officer, its President or one of its Vice Presidents, its Treasurer or its Assistant Treasurer, attested by its Secretary or one of its Assistant Secretaries. The signature of any of these officers on the Guarantee may be manual or facsimile.

     Securities or the Guarantee bearing the manual or facsimile signatures of individuals who were at any time the proper officers of the Company or the Guarantors, as applicable, shall bind the Company or the Guarantors, as applicable, notwithstanding that such individuals or any of them have ceased to hold such offices prior to the authentication and delivery of such Securities or did not hold such offices at the date of such Securities.

     At any time and from time to time after the execution and delivery of this Indenture, the Company may deliver Securities of any series executed by the Company and, if applicable, having endorsed thereon the Guarantees executed as provided in Section 1502 to the Trustee for authentication, together with a Company Order for the authentication and delivery of such Securities, and the Trustee in accordance with the Company Order (which may provide that Securities that are the subject thereof will be authenticated and delivered by the Trustee from time to time upon the telephonic or written order of Persons designated in said Company Order and that such Persons are authorized to determine such terms and conditions of said Securities as are specified in the Company Order) shall authenticate and deliver such Securities. If the form or terms of the Securities of the series have been established by or pursuant to one or more Board Resolutions as permitted by Sections 201 and 301, in authenticating such Securities, and accepting the additional responsibilities under this Indenture in relation to such Securities, the Trustee shall receive, and (subject to Section 601) shall be fully protected in conclusively relying upon, a copy of such Board Resolution, the Officers’ Certificate setting forth the terms of the series and an Opinion of Counsel, with such Opinion of Counsel stating,

     (1) if the form of such Securities has been established by or pursuant to Board Resolutions as permitted by Section 201, that such form has been established in conformity with the provisions of this Indenture;

     (2) if the terms of such Securities have been established by or pursuant to Board Resolutions as permitted by Section 301, that such terms have been established in conformity with the provisions of this Indenture;

     (3) that this Indenture and such Securities, when authenticated and delivered by the Trustee and issued by the Company in the manner and subject to any conditions specified in such Opinion of Counsel, will constitute valid and legally binding obligations of the Company, and, if applicable, the Guarantees endorsed thereon will constitute valid and legally binding obligations of the Guarantors, in each case enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles; and

     (4) that all laws and requirements in respect of the execution and delivery by the Company of such Securities have been complied with.

     However, the Trustee shall not be required to authenticate such Securities if the issue of such Securities pursuant to this Indenture will affect the Trustee’s own rights, duties or immunities under the Securities and this Indenture or otherwise in a manner which is not reasonably acceptable to the Trustee.

     Notwithstanding the provisions of Section 301 and of the preceding paragraph, if all Securities of a series are not to be originally issued at one time, it shall not be necessary to deliver the Officers’ Certificate otherwise required pursuant to Section 301 or the Company Order and Opinion of Counsel otherwise required pursuant to such preceding paragraph at or prior to the authentication of each Security of such series if such documents are delivered at or prior to the authentication upon original issuance of the first Security of such series to be issued.

     Each Security shall be dated the date of its authentication.

     No Security or Guarantee endorsed thereon shall be entitled to any benefit under this Indenture or be valid or obligatory for any purpose unless there appears on such Security a certificate of authentication substantially in the form provided for herein executed by the Trustee by manual signature, and such certificate upon any Security shall be conclusive evidence, and the only evidence, that such Security has been duly authenticated and delivered hereunder. Notwithstanding the foregoing, if any Security shall have been authenticated and delivered hereunder but never issued and sold by the Company, and the Company shall deliver such Security to the Trustee for cancellation as provided in Section 309, for all purposes of this Indenture such Security shall be deemed never to have been authenticated and delivered hereunder and shall never be entitled to the benefits of this Indenture.

      Section 304. Temporary Securities.

     Pending the preparation of definitive Securities of any series, the Company may execute, and upon Company Order the Trustee shall authenticate and deliver, temporary Securities which are printed, lithographed, typewritten, mimeographed or otherwise produced, in any authorized denomination, substantially of the tenor of the definitive Securities in lieu of which they are issued and with such appropriate insertions, omissions, substitutions and other variations as the officers executing such Securities may determine, as evidenced by their execution of such Securities.

     If temporary Securities of any series are issued, the Company will cause definitive Securities of that series to be prepared without unreasonable delay. After the preparation of definitive Securities of such series, the temporary Securities of such series shall be exchangeable for definitive Securities of such series upon surrender of the temporary Securities of such series at the office or agency of the Company in a Place of Payment for that series, without charge to the Holder. Upon surrender for cancellation of any one or more temporary Securities of any series, the Company shall execute and the Trustee shall authenticate and deliver in exchange therefor one or more definitive Securities of the same series, of any authorized denominations and of like tenor and aggregate principal amount. Until so exchanged, the temporary Securities of any series shall in all respects be entitled to the same benefits under this Indenture as definitive Securities of such series and tenor.

      Section 305. Registration; Registration of Transfer and Exchange.

     The Company shall cause to be kept at the Corporate Trust Office of the Trustee a register (the register maintained in such office or in any other office or agency of the Company in a Place of Payment being herein sometimes collectively referred to as the “ Security Register ”) in which, subject to such reasonable regulations as it may prescribe, the Company shall provide for the registration of Securities and of transfers of Securities. The Trustee initially is hereby appointed “Security Registrar” for the purpose of registering Securities and transfers of Securities as herein provided. The Company may change any Security Registrar without prior notice to any Holder. The Company or any of its Subsidiaries may act as Security Registrar.

     Upon surrender for registration of transfer of any Security of a series at the office or agency of the Company in a Place of Payment for that series, the Company shall execute, and the Trustee shall authenticate and deliver, in the name of the designated transferee or transferees, one or more new Securities of the same series, of any authorized denominations and of like tenor and aggregate principal amount, and having endorsed thereon a Guarantee executed by the Guarantors.

     At the option of the Holder, Securities of any series may be exchanged for other Securities of the same series, of any authorized denominations and of like tenor and aggregate principal amount, upon surrender of the Securities to be exchanged at such office or agency. Whenever any Securities are so surrendered for exchange, the Company shall execute, and the Trustee shall authenticate and deliver, the Securities which the Holder making the exchange is entitled to receive, and having endorsed thereon a Guarantee executed by the Guarantor.

     All Securities and the Guarantee endorsed thereon issued upon any registration of transfer or exchange of Securities and the Guarantee endorsed thereon, shall be the valid obligations of the Company and the Guarantors, respectively evidencing the same debt, and entitled to the same benefits under this Indenture, as the Securities and the Guarantee endorsed thereon surrendered upon such registration of transfer or exchange.

     Every Security presented or surrendered for registration of transfer or for exchange shall (if so required by the Company or the Trustee) be duly endorsed, or be accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed, by the Holder thereof or its attorney duly authorized in writing.

     No service charge shall be made for any registration of transfer or exchange of Securities, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge that may be imposed in connection with any registration of transfer or exchange of Securities, other than exchanges pursuant to Sections 304, 906 or 1107 not involving any transfer.

     If the Securities of any series (or of any series and specified tenor) are to be redeemed in part, the Company shall not be required (A) to issue, register the transfer of or exchange any Securities of that series (or of that series and specified tenor, as the case may be) during a period beginning at the opening of business 15 days before the day of the mailing of a notice of redemption of any such Securities selected for redemption under Section 1103 and ending at the close of business on the day of such mailing, or (B) to register the transfer of or exchange any Security so selected for redemption in whole or in part, except the unredeemed portion of any Security being redeemed in part.

     The provisions of Clauses (1), (2), (3) and (4) below shall apply only to Global Securities:

     (1) Each Global Security authenticated under this Indenture shall be registered in the name of the Depositary designated for such Global Security or a nominee thereof and delivered to such Depositary or a nominee thereof or custodian therefor, and each such Global Security shall constitute a single Security for all purposes of this Indenture.

     (2) Notwithstanding any other provision in this Indenture, no Global Security may be exchanged in whole or in part for Securities registered, and no transfer of a Global Security in whole or in part may be registered, in the name of any Person other than the Depositary for such Global Security or a nominee thereof unless (A) such Depositary (i) has notified the Company that it is unwilling or unable to continue as Depositary for such Global Security or (ii) has ceased to be a clearing agency registered under the Exchange Act, (B) there shall have occurred and be continuing an Event of Default with respect to such Global Security or (C) there shall exist such circumstances, if any, in addition to or in lieu of the foregoing as have been specified for this purpose as contemplated by Section 301.

     (3) Subject to Clause (2) above, any exchange of a Global Security for other Securities may be made in whole or in part, and all Securities issued in exchange for a Global Security or any portion thereof shall be registered in such names as the Depositary for such Global Security shall direct.

     (4) Every Security authenticated and delivered upon registration of transfer of, or in exchange for or in lieu of, a Global Security or any portion thereof, whether pursuant to this Section, Section 304, 306, 906 or 1107 or otherwise, shall be authenticated and delivered in the form of, and shall be, a Global Security, unless such Security is registered in the name of a Person other than the Depositary for such Global Security or a nominee thereof.

      Section 306. Mutilated, Destroyed, Lost and Stolen Securities.

     If any mutilated Security is surrendered to the Trustee, the Company shall execute and the Trustee shall authenticate and deliver in exchange therefor a new Security of the same series and of like tenor and principal amount and bearing a number not contemporaneously outstanding, and having endorsed thereon a Guarantee executed by the Guarantors, if applicable.

     If there shall be delivered to the Company and the Trustee (i) evidence to their satisfaction of the destruction, loss or theft of any Security and (ii) such security or indemnity as may be required by them to save each of them and any agent of either of them harmless, then, in the absence of notice to the Company or the Trustee that such Security has been acquired by a bona fide purchaser, the Company shall execute and the Trustee shall authenticate and deliver, in lieu of any such destroyed, lost or stolen Security, a new Security of the same series and

of like tenor and principal amount and bearing a number not contemporaneously outstanding, and having endorsed thereon a Guarantee executed by the Guarantors, if applicable.

     In case any such mutilated, destroyed, lost or stolen Security has become or is about to become due and payable, the Company in its discretion may, instead of issuing a new Security, pay such Security.

     Upon the issuance of any new Security under this Section, the Company may require the payment of a sum sufficient to cover any tax or other governmental charge that may be imposed in relation thereto and any other expenses (including the fees and expenses of the Trustee) connected therewith.

     Every new Security of any series and the Guarantee endorsed thereon, issued pursuant to this Section in lieu of any destroyed, lost or stolen Security shall constitute an original additional contractual obligation of the Company and the Guarantors, as applicable, whether or not the destroyed, lost or stolen Security shall be at any time enforceable by anyone, and shall be entitled to all the benefits of this Indenture equally and proportionately with any and all other Securities of that series duly issued hereunder.

     The provisions of this Section are exclusive and shall preclude (to the extent lawful) all other rights and remedies with respect to the replacement or payment of mutilated, destroyed, lost or stolen Securities.

      Section 307. Payment of Interest; Interest Rights Preserved.

     Except as otherwise provided in or as contemplated by Section 301 with respect to any series of Securities, interest on any Security which is payable, and is punctually paid or duly provided for, on any Interest Payment Date shall be paid to the Person in whose name that Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest; provided that on the maturity date for any series of Securities, the Company will pay accrued and unpaid interest to the Person to whom the Company pays the principal amount, instead of the Person in whose name that Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date.

     In the case of Securities represented by a Global Security registered in the name of or held by a Depository or its nominee, unless otherwise specified by Section 301, payment of principal, premium, if any, and interest, if any, will be made to the Depository or its nominee, as the case may be, as the registered owner or Holder of such Global Security. None of the Company, the Guarantors, the Trustee and the Paying Agent, any Authenticating Agent or the Security Registrant for such Securities will have any responsibility or liability for any aspect of the records relating to or payments made on account of a beneficial ownership interest in a Global Security or maintaining, supervising or reviewing any records relating to such beneficial ownership interests.

     Any interest on any Security of any series which is payable, but is not punctually paid or duly provided for, on any Interest Payment Date (herein called “ Defaulted Interest ”) shall forthwith cease to be payable to the Holder on the relevant Regular Record Date by virtue of having been such Holder, and such Defaulted Interest may be paid by the Company, at its election in each case, as provided in Clause (1) or (2) below:

     (1) The Company may elect to make payment of any Defaulted Interest to the Persons in whose names the Securities of such series (or their respective Predecessor S