AGREEMENT AND PLAN OF MERGER by and among PLAINS ALL AMERICAN PIPELINE, L.P. PAA ACQUISITION COMPANY LLC and PNGS GP LLC PAA NATURAL GAS STORAGE, L.P. Dated as of October 21, 2013

(b)                                 Capitalization.

(i)                                     As of September 15, 2013:

(A)                               there were 342,950,166 PAA Common Units issued and outstanding;

(B)                               there were 5,375,400 PAA Phantom Units issued and outstanding pursuant to the PAA LTIP, which PAA Phantom Units were convertible into 4,278,301 PAA Common Units, in the aggregate; and

(C)                               except as set forth in this Section 5.2(b)(i)(i) and Section 5.2(b)(ii), there were no other equity interests in PAA issued or outstanding.

(ii)                                  Each of the limited partner interests described in clause (i)(A) through (i)(B) above has been duly authorized and validly issued in accordance with applicable Laws and the PAA Partnership Agreement, and is fully paid (to the extent required under the PAA Partnership Agreement) and non-assessable (except to the extent such nonassessability may be affected by Sections 17-607 and 17-804 of DRULPA).  Such limited partner interests were not issued in violation of any preemptive or similar rights or any other agreement or understanding binding on PAA.  PAA GP is the sole general partner of PAA, owning all of the outstanding 2% general partner interest in PAA.  AAP owns all of the outstanding incentive distribution rights of PAA.

(iii)                               The New Common Units to be issued in accordance with this Agreement have been duly authorized and, when issued, will be fully paid (to the extent required under the PAA Partnership Agreement) and non-assessable (except to the extent such nonassessability may be affected by Sections 17-607 and 17-804 of DRULPA).

(iv)                              As of the date hereof, except for (x) PAA Common Units authorized for issuance upon conversion of PAA Phantom Units under the PAA LTIP, (y) equity securities owned by PAA or Plains GP in Subsidiaries of PAA or Plains GP and (z) PAA Common Units and other equity securities authorized or reserved for issuance pursuant to effective registration statements as of the date hereof that have been filed by PAA or its Subsidiaries with the SEC, (A) there are no partnership interests, limited liability company interests or other equity securities of any Buyer Party or any of their Subsidiaries issued or authorized and reserved for issuance, (B) there are no outstanding options, warrants, preemptive rights, subscriptions, calls or other rights, convertible securities, exchangeable securities, agreements or commitments of any character obligating any Buyer Party or any of their respective Subsidiaries to issue, transfer or sell any partnership or other equity interest of such Buyer Party or such Subsidiary of a Buyer Party or any securities convertible into or exchangeable or exercisable for such partnership interests or equity interests, or any commitment to authorize, issue or sell the same or any such equity securities, except pursuant to this Agreement, and (C) there are no contractual obligations of any Buyer Party or any of their respective Subsidiaries to repurchase, redeem or otherwise acquire any partnership interest or other equity interest

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in such person or any of its Subsidiaries or any such securities or agreements listed in clause (B) of this sentence.

(c)                                  Power, Authority and Approvals of Transactions.  Each of the Buyer Parties has the requisite limited partnership or limited liability company power and authority to execute, deliver and perform its obligations under this Agreement and to consummate the Merger Transactions.  This Agreement and the Merger Transactions have been authorized by all necessary limited partnership or limited liability company action by the Buyer Parties.  This Agreement has been duly executed and delivered by each Buyer Party and constitutes a valid and binding agreement of each Buyer Party (assuming the due execution and delivery of this Agreement by, or on behalf of, the Other Parties), enforceable against each such Buyer Party in accordance with its terms (except as such enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer and similar Laws of general applicability relating to or affecting creditors’ rights or by general equity principles (regardless of whether such enforceability is considered in a proceeding in equity or at law)).

(d)                                 No Violations or Defaults.  Subject to the declaration of effectiveness of the Registration Statement, required filings under federal and state securities laws and with the NYSE, assuming the other consents and approvals contemplated by Section 5.2(e) and Article VII are obtained and assuming the consents, waivers and approvals specified in Section 6.10(a) are obtained, the execution, delivery and performance of this Agreement and the consummation of the Merger Transactions by the Buyer Parties do not and will not (i) except as would not reasonably be expected to have a Material Adverse Effect with respect to the Buyer Parties, (x) constitute a breach or violation of, or result in a default (or an event that, with notice or lapse of time or both, would become a default) under, or result in the termination or in a right of termination or cancellation of, or accelerate the performance required by, any note, bond, mortgage, indenture, deed of trust, license, franchise, lease, contract, agreement, joint venture or other instrument or obligation to which PAA or any of its Subsidiaries is a party or by which PAA or any of its Subsidiaries or properties is subject or bound, (y) contravene or conflict with or constitute a material violation of any provision of any Law binding upon or applicable to the Buyer Parties or any of their respective Subsidiaries or (z) result in the creation of any Lien on any of the assets of the Buyer Parties or their respective Subsidiaries’ assets, (ii) constitute a breach or violation of, or a default under, the organizational documents of any Buyer Party, or (iii) cause the Merger Transactions to be subject to Takeover Laws.

(e)                                  Consents and Approvals.  No consents or approvals of, or filings or registrations with, any Governmental Authority are necessary in connection with (i) the execution and delivery by the Buyer Parties of this Agreement or (ii) the consummation by the Buyer Parties of the Merger Transactions, except for (A) the filing of any required applications or notices with any state or foreign agencies of competent jurisdiction and approval of such applications or notices, (B) the filing with the SEC of the Registration Statement and the Proxy Statement/Prospectus, (C) the filing of the Certificate of Merger with the Secretary of State of the State of Delaware, (D) any consents, authorizations, approvals, filings or exemptions in connection with compliance with the rules of the NYSE, (E) such filings and approvals as may be required to be made or obtained under the securities or “Blue Sky” laws of various states in connection with the issuance of New Common Units pursuant to this Agreement, and (F) such other consents, authorizations, approvals, filings or registrations the absence or unavailability of

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which could not, either individually or in the aggregate, reasonably be expected to have a Material Adverse Effect with respect to PAA.

(f)                                   Financial Reports and the PAA SEC Documents.  The PAA SEC Documents, as of their respective dates, (i) complied in all material respects as to form with the applicable requirements of the Securities Act or the Exchange Act, as the case may be, and (ii) did not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements made therein, in the light of the circumstances under which they were made, not misleading.  The historical financial statements of PAA and its consolidated subsidiaries contained in or incorporated by reference into any such PAA SEC Document (including the related notes and schedules thereto) (A) comply in all material respects with the applicable requirements of the Securities Act and the Exchange Act, and (B) fairly present the financial position, results of operations, partners’ equity and cash flows, as the case may be, of the entity or entities to which they relate as of the dates or for the periods to which such financial statements relate, in each case in accordance with U.S. generally accepted accounting principles consistently applied during the periods involved, except in each case as may be noted therein, subject to normal year-end audit adjustments in the case of unaudited statements.

(g)                                  Absence of Undisclosed Liabilities.  Except as disclosed in the audited financial statements (or notes thereto) included in PAA’s Annual Report on Form 10-K for the year ended December 31, 2012, and in the financial statements (or notes thereto) included in subsequent PAA SEC Documents filed by PAA prior to the date hereof, neither PAA nor any of its consolidated subsidiaries had at December 31, 2012, or has incurred since that date, any liabilities or obligations (whether absolute, accrued, contingent or otherwise) of any nature, except (i) liabilities, obligations or contingencies that (A) are accrued or reserved against in the financial statements of PAA included in the PAA SEC Documents filed prior to the date hereof, or reflected in the notes thereto, (B) were incurred since December 31, 2012 in the ordinary course of business or (C) relate to this Agreement, the Merger Transactions or the proposal of PAA with respect to the Merger or (ii) liabilities, obligations or contingencies that (A) would not reasonably be expected, either individually or in the aggregate, to have a Material Adverse Effect on PAA or (B) that have been discharged or paid in full prior to the date hereof.  Notwithstanding anything to the contrary herein, PAA makes no representation or warranty with respect to any liability or obligation of MLP or any of its Subsidiaries.

(h)                                 Compliance with Law.  PAA and each of its Subsidiaries is in compliance with and is not in default under or in violation of any applicable Law, except where such non-compliance, default or violation would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect on PAA.  Since December 31, 2012, neither PAA nor any of its Subsidiaries has received any written notice from any Governmental Authority regarding any actual or possible violation of, or failure to comply with, any Law, except as would not reasonably be expected to have, individually or in the aggregate, a Material Adverse Effect on PAA.

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(i)                                     Material Contracts.

(i)                                     Except for this Agreement, as of the date hereof, neither PAA nor any of its Subsidiaries is a party to or bound by any PAA Material Contract that is required to be filed as an exhibit to the PAA SEC Documents that has not been so filed.

(ii)                                  Except as would not reasonably be expected to have a Material Adverse Effect on PAA, each PAA Material Contract is valid and binding and in full force and effect,  (A) no event or condition exists which constitutes a default on the part of PAA or any of its Subsidiaries under any such PAA Material Contract, and (B) to the Knowledge of PAA, no other party to such PAA Material Contract is in default in any respect thereunder.

(j)                                    Operations of MergerCo.  MergerCo was formed solely for the purpose of engaging in the Merger Transactions and has engaged in no business other than in connection with entering into this Agreement and engaging in the Merger Transactions.

(k)                                 No Brokers.  No action has been taken by the Buyer Parties that would give rise to any valid claim against any party hereto for a brokerage commission, finder’s fee or other like payment with respect to the Merger Transactions.

(l)                                     Ownership of MLP Common Units.  As of September 15, 2013, PAA owns (i) 28,155,526 MLP Common Units, which represent all MLP Common Units held by any Buyer Party or any of its respective Subsidiaries or MLP GP, (ii) 11,934,351 MLP Subordinated Series A Units and (iii) 13,500,000 MLP Series B Subordinated Units.

(m)                             No Material Adverse Effect.  Since December 31, 2012 to the date of this Agreement, there has not been a Material Adverse Effect with respect to PAA.

(n)                                 Investigation; No Other Representations and Warranties.

(i)                                     Each of the Buyer Parties has conducted its own independent review and analysis of the business, operations, assets, liabilities, results of operations, financial condition and prospects of MLP, MLP GP and their Subsidiaries and acknowledges that each of the Buyer Parties has been provided access for such purposes.  In entering into this Agreement, each of the Buyer Parties has relied solely upon its independent investigation and analysis of MLP, MLP GP and their Subsidiaries, and each of the Buyer Parties acknowledges and agrees that it has not been induced by and has not relied upon any representations, warranties or statements, whether express or implied, made by MLP, MLP GP, any of their Subsidiaries, or any of their respective Affiliates or Representatives, that are not expressly set forth in this Agreement, whether or not such representations, warranties or statements were made in writing or orally.  Each of the Buyer Parties acknowledges and agrees that, to the fullest extent permitted by applicable Law, MLP, MLP GP and their Subsidiaries, and their respective Affiliates or Representatives, shall have no liability or responsibility whatsoever to the Buyer Parties or their respective Affiliates or Representatives on any basis (including in contract or tort, under federal or state securities Laws or otherwise) based upon any information (including any statement, document or agreement delivered in connection with this

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Agreement and any financial statements and any projections, estimates or other forward-looking information) provided or made available (including in any data room, management presentation, information or descriptive memorandum or supplemental information), or oral or written statements made (or any omissions therefrom), to the Buyer Parties or their respective Affiliates or Representatives, except for the representations and warranties of the MLP Parties expressly set forth in Section 5.1 (subject to the qualifications set forth therein).

(ii)                                  The Buyer Parties each acknowledge and agree that, except for the representations and warranties expressly set forth in Section 5.1 (subject to the qualifications set forth therein) (i) the MLP Parties do not make, and have not made, any representations or warranties relating to itself or its Subsidiaries or their respective businesses or otherwise in connection with the Merger, (ii) no person has been authorized by MLP or MLP GP to make any representation or warranty relating to any MLP Party or its Subsidiaries or their respective businesses or otherwise in connection with the Merger, and if made, such representation or warranty must not be relied upon by the Buyer Parties as having been authorized by such party and (iii) any estimates, projections, predictions, data, financial information, memoranda, presentations or any other materials or information provided or addressed to the Buyer Parties or any of their Representatives are not and shall not be deemed to be or include representations or warranties unless any such materials or information is the subject of an express representation or warranty set forth in Section 5.1 of this Agreement.

ARTICLE VI
COVENANTS

The MLP Parties hereby covenant to and agree with PAA, and the Buyer Parties hereby covenant to and agree with MLP, that:

Section 6.1                                    Efforts.  Subject to the terms and conditions of this Agreement, such parties shall use their commercially reasonable efforts in good faith (subject to, and in accordance with, applicable Laws) to take, or cause to be taken, all actions, and to do, or cause to be done, all things necessary, proper, desirable or advisable, so as to permit and enable prompt consummation of the Merger Transactions, including (a) using commercially reasonable efforts to lift or rescind any injunction or restraining order or other order adversely affecting the ability of the parties to consummate the Merger Transactions and (b) using commercially reasonable efforts to defend any litigation seeking to enjoin, prevent or delay the consummation of the Merger Transactions or seeking material damages. Each of such parties shall (x) cooperate fully with the Other Parties hereto to that end and (y) furnish to the Other Parties copies of all correspondence, filings and communications between it and its Affiliates and any Governmental Authority with respect to the Merger Transactions.

Section 6.2                                    Unitholder Approval.

(a)                                 Subject to the terms and conditions of this Agreement, and except as permitted by Section 6.2(b), MLP shall take, in accordance with applicable Law, applicable stock exchange rules and the MLP Partnership Agreement, all action necessary to call, hold and convene the

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MLP Meeting to consider and vote upon the approval of this Agreement and the Merger Transactions, as promptly as practicable after the Registration Statement is declared effective.  Subject to Section 6.2(b), the MLP GP Conflicts Committee shall recommend approval of this Agreement and the Merger Transactions to the holders of MLP Common Units (the “MLP Recommendation”), and MLP shall take all reasonable lawful action to solicit such approval by the holders of MLP Common Units.  Except as provided in Section 6.2(b), neither the MLP GP Conflicts Committee nor the MLP GP Board shall (A) withdraw, modify or qualify in any manner adverse to PAA the MLP Recommendation or (B) publicly approve, adopt or recommend, or publicly propose to approve, adopt or recommend, any Acquisition Proposal (any action described in this sentence being referred to as an “MLP Change in Recommendation”).  None of MLP GP, MLP or any of their Subsidiaries shall execute or enter into any letter of intent, memorandum of understanding, agreement in principle, merger agreement, acquisition agreement, option agreement, joint venture agreement, partnership agreement or other similar contract providing for any Acquisition Proposal.

(b)                                 Notwithstanding Section 6.2(a), at any time prior to obtaining the MLP Unitholder Approval, the MLP GP Conflicts Committee or the MLP GP Board may make an MLP Change in Recommendation if it has determined in good faith, after consultation with its outside legal counsel and financial advisors, that failure to make an MLP Change in Recommendation would be inconsistent with its duties under the MLP Partnership Agreement or applicable Law; provided, however, that neither the MLP GP Conflicts Committee nor the MLP GP Board shall be entitled to exercise its right to make an MLP Change in Recommendation unless (i) MLP has provided to PAA three Business Days prior written notice (such notice, a “Notice of Proposed Recommendation Change”) advising PAA that the MLP GP Conflicts Committee or the MLP GP Board intends to take such action, specifying the reasons therefor in reasonable detail and if such action is in response to any Acquisition Proposal, such Acquisition Proposal is not the result of a material breach of Section 6.6 and the Notice of Proposed Recommendation Change specifies the material terms and conditions of such Acquisition Proposal, the identity of the Person making such Acquisition Proposal and affirmatively states that the MLP GP Conflicts Committee has determined that such proposal constitutes a Superior Proposal, (ii) each of MLP and the MLP GP Conflicts Committee has negotiated, and has used its commercially reasonable efforts to cause its Representatives to negotiate, in good faith with PAA during such notice period to enable PAA to revise the terms of this Agreement such that it would obviate the need for making the MLP Change in Recommendation, and (iii) following the end of such notice period, the MLP GP Conflicts Committee shall have considered in good faith any changes to this Agreement proposed by PAA and shall have determined that the failure to make an MLP Change in Recommendation would continue to be inconsistent with its duties under the MLP Partnership Agreement or applicable Law even if such revisions proposed by PAA were to be given effect.  Any MLP Change in Recommendation shall not invalidate the approval (or “Special Approval” as defined in the MLP Partnership Agreement) of this Agreement or any other approval of the MLP GP Conflicts Committee, including in any respect that would have the effect of causing any state (including Delaware) takeover statute or other similar statute to be applicable to the Merger Transactions.

(c)                                  Notwithstanding anything to the contrary in this Agreement, if there occurs an MLP Change in Recommendation in accordance with this Agreement, MLP and MLP GP shall, upon request of the MLP GP Conflicts Committee, (i) no longer call, hold or convene the MLP

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Meeting to consider and vote upon the approval of this Agreement and the Merger Transactions, and (ii) cancel any previously called MLP Meeting.

(d)                                 Nothing contained in this Agreement shall prevent MLP, MLP GP, the MLP GP Board or the MLP GP Conflicts Committee from taking and disclosing to the holders of MLP Common Units a position contemplated by Rule 14d-9 and Rule 14e-2(a) promulgated under the Exchange Act (or any similar communication to holders of MLP Common Units) or from making any legally required disclosure to holders of MLP Common Units. Any “stop-look-and-listen” communication by MLP, MLP GP, the MLP GP Board, or the MLP GP Conflicts Committee to the limited partners of MLP pursuant to Rule 14d-9(f) promulgated under the Exchange Act (or any similar communication to the holders of MLP Common Units) shall not be considered an MLP Change in Recommendation or a withdrawal, modification or change in any manner adverse to PAA of all or a portion of the MLP GP Conflicts Committee Approval.

Section 6.3                                    Registration Statement.

(a)                                 Each of the Buyer Parties and the MLP Parties agrees to cooperate in the preparation of the Registration Statement (including the Proxy Statement/Prospectus constituting a part thereof and all related documents) to be filed by PAA with the SEC in connection with the issuance of the New Common Units in the Merger as contemplated by this Agreement.  PAA agrees to file the Registration Statement with the SEC as promptly as reasonably practicable.  Each of MLP and PAA agrees to use all commercially reasonable efforts to cause the Registration Statement to be declared effective under the Securities Act as promptly as practicable after filing thereof.  PAA also agrees to use commercially reasonable efforts to obtain all necessary state securities law or “Blue Sky” permits and approvals required to carry out the Merger Transactions.  Each of PAA and MLP agrees to furnish to the other party all information concerning PAA and its Subsidiaries or MLP, MLP GP and its Subsidiaries, as applicable, and the officers, directors and unitholders of PAA and MLP and any applicable Affiliates, as applicable, and to take such other action as may be reasonably requested in connection with the foregoing. No filing of the Registration Statement will be made by PAA, and no filing of the Proxy Statement/Prospectus will made by PAA or MLP, in each case without providing the other party a reasonable opportunity to review and comment thereon.

(b)                                 Each of the MLP Parties and PAA agrees, as to itself and its Subsidiaries, that (i) none of the information supplied or to be supplied by it for inclusion or incorporation by reference in the Registration Statement will, at the time the Registration Statement and each amendment or supplement thereto, if any, becomes effective under the Securities Act, contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein not misleading, and (ii) the Proxy Statement/Prospectus and any amendment or supplement thereto will, at the date of mailing to the holders of MLP Common Units and at the time of the MLP Meeting, not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.  Each of the MLP Parties and Buyer Parties further agrees that, if it shall become aware prior to the Closing Date of any information that would cause any of the statements in the Registration Statement or the Proxy Statement/Prospectus to be false or misleading with respect to any material fact, or omit to state any material fact necessary to make the statements therein,

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in the light of the circumstances under which they were made, not false or misleading, it will promptly inform the Other Parties thereof and take the necessary steps to correct such information in an amendment or supplement to the Registration Statement or the Proxy Statement/Prospectus.  No amendment or supplement to the Registration Statement will be made by PAA, and no amendment or supplement to the Proxy Statement/Prospectus will made by PAA or MLP, in each case without providing the other party a reasonable opportunity to review and comment thereon.

(c)                                  PAA will advise MLP, promptly after PAA receives notice thereof, of (i) the time when the Registration Statement has become effective or any supplement or amendment has been filed, (ii) the issuance of any stop order or the suspension of the qualification of the New Common Units for offering or sale in any jurisdiction, (iii) the initiation or threat of any proceeding for any such purpose, or (iv) any request by the SEC for the amendment or supplement of the Registration Statement or the Proxy Statement/Prospectus or for additional information.

(d)                                 MLP will use its commercially reasonable efforts to cause the Proxy Statement/Prospectus to be mailed to the MLP Unitholders as soon as practicable after the effective date of the Registration Statement.

Section 6.4                                    Press Releases.  Prior to an MLP Change in Recommendation, if any, neither MLP nor PAA shall, without the prior approval of (a) the MLP GP Conflicts Committee, in the case of PAA, and (b) PAA, in the case of MLP, issue any press release or written statement for general circulation relating to the Merger Transactions, except as otherwise required by applicable Law or the rules of the NYSE, in which case it will consult with the other party before issuing any such press release or written statement.

Section 6.5                                    Access; Information.

(a)                                 Subject to applicable Laws relating to the exchange of information, each party shall, and shall cause its Subsidiaries to furnish promptly to such Person and its Representatives a copy of each material report, schedule and other document filed by it pursuant to the requirements of federal or state securities law (other than reports or documents that PAA or MLP or their respective Subsidiaries, as the case may be, are not permitted to disclose under applicable Law).  Notwithstanding the foregoing, neither MLP nor PAA nor any of their respective Subsidiaries shall be required to provide access to or to disclose information where such access or disclosure would jeopardize the attorney-client privilege (or other applicable privilege or immunity) of the institution in possession or control of such information or contravene any Law, fiduciary duty or binding agreement entered into prior to the date of this Agreement.

(b)                                 PAA and MLP, respectively, will not use any information obtained pursuant to this Section 6.5 (to which it was not entitled under Law or any agreement other than this Agreement) for any purpose unrelated to (i) the consummation of the Merger Transactions or (ii) the matters contemplated by Section 6.2 in accordance with the terms thereof, and will hold all information and documents obtained pursuant to this Section 6.5 in confidence.  No investigation by either party of the business and affairs of the other shall affect or be deemed to modify or

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waive any representation, warranty, covenant or agreement in this Agreement, or the conditions to either party’s obligation to consummate the Merger Transactions.

Section 6.6                                    Acquisition Proposals.

(a)                                 MLP GP and MLP shall, and they shall cause the Subsidiaries and Representatives of MLP GP and MLP to, immediately cease and terminate any solicitation, encouragement, discussions or negotiations with any Person that may be ongoing with respect to or that may reasonably be expected to lead to, an Acquisition Proposal.

(b)                                 Neither MLP GP nor MLP shall, and they shall use their commercially reasonable efforts to cause the Subsidiaries and Representatives of MLP GP and MLP not to, directly or indirectly, (i) initiate, solicit, knowingly encourage or knowingly facilitate (including by way of furnishing information) any inquiries regarding, or the making or submission of any proposal or offer that constitutes, or may reasonably be expected to lead to, an Acquisition Proposal, (ii) conduct or participate in any discussions or negotiations regarding any Acquisition Proposal, or (iii) furnish to any Person any non-public information or data relating to MLP or any of its Subsidiaries.  Notwithstanding the foregoing, at any time prior to obtaining MLP Unitholder Approval, the MLP GP Conflicts Committee may take the actions described in clauses (ii) and (iii) of this Section 6.6(b) with respect to any Person that makes a bona fide written Acquisition Proposal that did not result from a material breach of this Section 6.6(b), if (A) the MLP GP Conflicts Committee, after consultation with its outside legal counsel and financial advisors, determines in good faith that such Acquisition Proposal constitutes or could reasonably be expected to result in a Superior Proposal and that the failure to take such action would be inconsistent with its duties under the MLP Partnership Agreement or applicable Law, and (B) prior to furnishing any such non-public information to such Person, MLP receives from such Person an executed confidentiality agreement with reasonable customary terms as to the treatment of confidential information.  MLP GP and MLP shall, as promptly as practicable (and in any event within 48 hours), advise PAA in writing of any Acquisition Proposal received from any third Person, including the identity of such third Person, or any request for discussions or negotiations with respect to any Acquisition Proposal, and the material terms of such Acquisition Proposal or request, as well as the identity of the Person making such proposal or request.  MLP GP and MLP shall, as promptly as practicable (and in all events within 48 hours), provide to PAA copies of any written materials received by MLP GP, MLP or any of their Subsidiaries or Representatives in connection with any of the foregoing.

(c)                                  MLP GP and MLP shall keep PAA reasonably informed of any material developments regarding or changes in any Acquisition Proposal on a reasonably current basis (and in all events within 36 hours of such material development).  MLP GP and MLP agree that they and their Subsidiaries will not enter into any confidentiality agreement with any Person that prohibits MLP GP or MLP or any of their Subsidiaries from providing any information to PAA in accordance with Section 6.5 or this Section 6.6.

(d)                                 The MLP Parties acknowledge that the agreements contained in this Section 6.6 are an integral part of the Merger Transactions, and that, without these agreements, the Buyer Parties would not have entered into this Agreement.

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Section 6.7                                    Takeover Laws.  Neither MLP nor PAA shall take any action that would cause the Merger Transactions to be subject to requirements imposed by any Takeover Laws, and each of them shall take all commercially reasonable steps within its control to exempt (or ensure the continued exemption of) the Merger Transactions from, or if necessary challenge the validity or applicability of, any applicable Takeover Law, as now or hereafter in effect, including Takeover Laws of any state that purport to apply to this Agreement or the Merger Transactions.

Section 6.8                                    No Rights Triggered.  MLP shall take all steps necessary to ensure that the entering into of this Agreement and the consummation of the Merger Transactions and any other action or combination of actions do not and will not result in the grant of any Rights to any person under the MLP Partnership Agreement or under any material agreement to which it or any of its Subsidiaries is a party.

Section 6.9                                    New Common Units Listed.  PAA shall use its commercially reasonable efforts to list, prior to the Closing, on the NYSE, upon official notice of issuance, the New Common Units.

Section 6.10                             Third-Party Approvals.

(a)                                 Subject to the terms and conditions of this Agreement, PAA and MLP and their respective Subsidiaries shall cooperate and use their respective commercially reasonable efforts to prepare all documentation, to effect all filings, to obtain all permits, consents, approvals and authorizations of all Governmental Authorities and third parties necessary to consummate the Merger Transactions, to comply with the terms and conditions of such permits, consents, approvals and authorizations and to cause the Merger to be consummated as expeditiously as practicable.  Each of PAA and MLP shall have the right to review in advance, and to the extent practicable each will consult with the other, in each case subject to applicable Laws relating to the exchange of information with respect to, all material written information submitted to any third party or any Governmental Authorities in connection with the Merger Transactions.  In exercising the foregoing right, each of the parties hereto agrees to act reasonably and promptly.  Each party hereto agrees that it will consult with the Other Parties with respect to the obtaining of all material permits, consents, approvals and authorizations of all third parties and Governmental Authorities necessary or advisable to consummate the Merger Transactions, and each party will keep the Other Parties apprised of the status of material matters relating to completion of the Merger Transactions.

(b)                                 Each of PAA and MLP agrees, upon request, to furnish the other party with all information concerning itself, its Subsidiaries, directors, officers and unitholders and such other matters as may be reasonably necessary or advisable in connection with any required filing, notice or application made by or on behalf of such Other Party or any of such Other Party’s Subsidiaries to any Governmental Authority in connection with the Merger Transactions.

Section 6.11                             Indemnification; Directors’ and Officers’ Insurance.

(a)                                 Without limiting any additional rights that any director, officer, trustee, employee, agent, or fiduciary may have under any employment or indemnification agreement or under the MLP Partnership Agreement, the MLP GP LLC Agreement, this Agreement or, if applicable,

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similar organizational documents or agreements of any of MLP’s Subsidiaries, from and after the Effective Time, PAA, MLP GP and the Surviving Entity, jointly and severally, shall:  (i) indemnify and hold harmless each person who is at the date hereof or during any period from the date hereof through the Effective Time serving as a director or officer of MLP GP or of any of its Subsidiaries or as a trustee of (or in a similar capacity with) any Compensation and Benefit Plan of any thereof (collectively, the “Indemnified Parties”) to the fullest extent authorized or permitted by applicable Law in connection with any Claim or Action and any losses, claims, damages, liabilities, costs, Indemnification Expenses, judgments, fines, penalties and amounts paid in settlement (including all interest, assessments and other charges paid or payable in connection with or in respect of any thereof) resulting therefrom; and (ii) promptly pay on behalf of or, within 15 days after any request for advancement, advance to each of the Indemnified Parties any Indemnification Expenses incurred in defending, serving as a witness with respect to or otherwise participating with respect to any Claim or Action in advance of the final disposition of such Claim or Action, including payment on behalf of or advancement to the Indemnified Party of any Indemnification Expenses incurred by such Indemnified Party in connection with enforcing any rights with respect to such indemnification and/or advancement, in each case without the requirement of any bond or other security.  The indemnification and advancement obligations of PAA, MLP GP and the Surviving Entity pursuant to this Section 6.11(a) shall extend to acts or omissions occurring at or before the Effective Time and any Claim or Action relating thereto (including with respect to any acts or omissions occurring in connection with the approval of this Agreement and the consummation of the Merger and the other Merger Transactions, including the consideration and approval thereof and the process undertaken in connection therewith and any Claim or Action relating thereto), and all rights to indemnification and advancement conferred hereunder shall continue as to any Indemnified Party who has ceased to be a director or officer of MLP GP after the date hereof and shall inure to the benefit of such person’s heirs, executors and personal and legal representatives.  As used in this Section 6.11:  (x) the term “Claim” means any threatened, asserted, pending or completed action or proceeding, whether instituted by any party hereto, any Governmental Authority or any other Person, or that any Indemnified Party in good faith believes might lead to the institution of any action or proceeding, whether civil, criminal, administrative, investigative or other, including any arbitration or other alternative dispute resolution mechanism (“Action”), arising out of or pertaining to matters that relate to such Indemnified Party’s duties or service as a director or officer of MLP GP or of any of its Subsidiaries or as a trustee of (or in a similar capacity with) any Compensation and Benefit Plan of any thereof; (y) the term “Indemnification Expenses” means reasonable attorneys’ fees and all other reasonable costs, expenses and obligations (including experts’ fees, travel expenses, court costs, retainers, transcript fees, duplicating, printing and binding costs, as well as telecommunications, postage and courier charges) paid or incurred in connection with investigating, defending, being a witness in or participating in (including on appeal), or preparing to investigate, defend, be a witness in or participate in, any Claim for which indemnification is sought pursuant to this Section 6.11(a), including any Action relating to a claim for indemnification or advancement brought by an Indemnified Party; and (z) the phrase “to the fullest extent authorized or permitted by applicable Law” shall include, but not be limited to, (1) to the fullest extent permitted by any provision of the DRULPA or the DLLCA that authorizes or permits additional indemnification by agreement or otherwise, or the corresponding provision of any amendment to or replacement of the DRULPA or the DLLCA, and (2) to the fullest extent authorized or permitted by any amendments to or replacements of the

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DRULPA or the DLLCA adopted after the date of this Agreement that increase the extent to which an entity may indemnify its directors, officers, trustees, employees, agents, or fiduciaries or persons serving in any capacity in which any Indemnified Party serves.  Any amendment, alteration or repeal of the DRULPA or the DLLCA that adversely affects any right of any Indemnified Party shall be prospective only and shall not limit or eliminate any such right with respect to any Claim or Action involving any occurrence or alleged occurrence of any action or omission to act that took place prior to such amendment or repeal.  Neither PAA, MLP GP nor the Surviving Entity shall settle, compromise or consent to the entry of any judgment in any actual or threatened Claim or Action in respect of which indemnification has been or could be sought by such Indemnified Party hereunder unless such settlement, compromise or judgment includes an unconditional release of such Indemnified Party from all liability arising out of such Claim or Action without admission or finding of wrongdoing, or such Indemnified Party otherwise consents thereto.

(b)                                 Without limiting the foregoing, the Buyer Parties and the MLP Parties agree that all rights to indemnification, advancement of expenses and exculpation from liabilities for acts or omissions occurring at or prior to the Effective Time now existing in favor of the Indemnitees as provided in the MLP Partnership Agreement or the MLP GP LLC Agreement (or, as applicable, the charter, bylaws, partnership agreement, limited liability company agreement, or other organizational documents of any of MLP’s Subsidiaries) and indemnification agreements of MLP or MLP GP or any of their respective Subsidiaries shall be assumed by the Surviving Entity, MLP GP and PAA in the Merger, without further action, at the Effective Time and shall survive the Merger and shall continue in full force and effect in accordance with their terms.

(c)                                  For a period of six years from the Effective Time, PAA shall maintain in effect the current directors’ and officers’ liability and fiduciary insurance policies with aggregate coverage limits no less that the policies in existence on the date hereof and covering the Indemnified Parties (but PAA may substitute therefor other policies, including an insurance tail policy, of at least the same coverage limits and that are no less advantageous to the Indemnified Parties so long as that substitution does not result in gaps or lapses in coverage) with respect to matters occurring on or before the Effective Time, but PAA shall not be required to pay annual premiums in excess of 300% of the last annual premiums paid therefor prior to the date hereof and shall purchase the maximum amount of coverage that can be obtained for that amount if the coverage described in this Section 6.11(c) would cost in excess of that amount.

(d)                                 If PAA, MLP GP or the Surviving Entity or any of their respective successors or assigns (i) consolidates with or merges with or into any other Person and shall not be the continuing or surviving corporation, partnership or other entity of such consolidation or merger, or (ii) transfers or conveys all or substantially all of its properties and assets to any Person, then, and in each such case, proper provision shall be made so that the successors and assigns of PAA, MLP GP or the Surviving Entity assume, including by operation of law, the obligations set forth in this Section 6.11.

(e)                                  This Section 6.11 shall survive the consummation of the Merger and is intended to be for the benefit of, and shall be enforceable by, the Indemnified Parties and the Indemnitees and their respective heirs and personal representatives, and shall be binding on PAA, MLP GP and the Surviving Entity and their respective successors and assigns.

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Section 6.12                             Notification of Certain Matters.  Each of MLP and PAA shall give prompt notice to the other of (a) any fact, event or circumstance known to it that (i) could reasonably be expected, individually or taken together with all other facts, events and circumstances known to it, to result in any Material Adverse Effect with respect to it or (ii) could cause or constitute a material breach of any of its representations, warranties, covenants or agreements contained herein, and (b) (i) any change in its financial condition or business that results in, or could reasonably be expected to result in, a Material Adverse Effect with respect to it or (ii) any litigation or governmental complaints, investigations or hearings, to the extent such litigation, complaints, investigations, or hearings relate to this Agreement or the Merger Transactions or result in a Material Adverse Effect with respect to it.

Section 6.13                             Rule 16b-3.  Prior to the Effective Time, MLP shall take such steps as may be reasonably requested by any party hereto to cause dispositions of MLP equity securities (including MLP Phantom Units) pursuant to the Merger Transactions by each individual who is a director or officer of MLP GP to be exempt under Rule 16b-3 promulgated under the Exchange Act in accordance with that certain No-Action Letter dated January 12, 1999 issued by the SEC regarding such matters.

Section 6.14                             MLP GP Conflicts Committee.  Prior to the Effective Time, neither any Buyer Party nor any of their Subsidiaries shall, without the consent of the MLP GP Conflicts Committee, eliminate the MLP GP Conflicts Committee, revoke or diminish the authority of the MLP GP Conflicts Committee or remove or cause the removal of any director of MLP GP that is a member of the MLP GP Conflicts Committee either as a director or as a member of such committee.  For the avoidance of doubt, this Section 6.14 shall not apply to the filling in accordance with the provisions of the MLP GP LLC Agreement of any vacancies caused by the death, incapacity or resignation of such director.

Section 6.15                             Distributions.  Each of MLP and PAA shall consult with the Other Party regarding the declaration and payment of distributions in respect of the MLP Common Units and the PAA Common Units and the record and payment dates relating thereto, so that no MLP Unitholder shall receive two distributions, or fail to receive one distribution, for any single calendar quarter with respect to its applicable MLP Common Units or any PAA Common Units any such MLP Unitholder receives in exchange therefor pursuant to the Merger.

Section 6.16                             Conversion of Equity Awards.

(a)                                 Adoption of MLP LTIP.  Subject to Section 6.16(c), prior to the Effective Time, the PAA Board or its Compensation Committee shall cause Plains GP to adopt the MLP LTIP as of the Effective Time, authorize the conversion of MLP Phantom Units into PAA Phantom Units in accordance with Section 3.1(g)(i)(i) at the Effective Time, and shall take such other actions as may be necessary to authorize the events contemplated in Section 3.1(g); such actions shall include the following:  (i) effective as of the Effective Time, the MLP LTIP shall be continued by Plains GP on behalf of PAA and all MLP obligations thereunder assumed by PAA (including obligations with respect to MLP Phantom Units in accordance with Section 3.1(g)(i)(i)) and such plan shall continue in effect subject to amendment, termination, and/or suspension in accordance with the terms of the MLP LTIP, notwithstanding the Merger, applicable laws and regulations and the applicable rules of any unit exchange; (ii) from and after the Effective Time all

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references to MLP Common Units in the MLP LTIP shall be substituted with references to PAA Common Units; (iii) the number of PAA Common Units that will be available for grant and delivery under the MLP LTIP from and after the Effective Time shall equal the number of MLP Common Units that were available for grant and delivery under the MLP LTIP immediately prior to the Effective Time, as adjusted to give effect to the Exchange Ratio (which number will include the number of PAA Common Units subject to the PAA Phantom Units that will be issued upon conversion of MLP Phantom Units in accordance with Section 3.1(g)); (iv) from and after the Effective Time, awards under the MLP LTIP may be granted only to those individuals who were eligible to receive awards under the MLP LTIP immediately before the Effective Time (including any individuals hired on and after the Effective Time who would have been eligible for such awards pursuant to the eligibility provisions of the MLP LTIP as in effect immediately prior to the Effective Time); and (v) no participant in the MLP LTIP shall have any right to acquire MLP Common Units under the MLP LTIP from and after the Effective Time.  PAA shall reserve for issuance a number of PAA Common Units equal to the number of PAA Common Units that will be available for grant and delivery under the MLP LTIP from and after the Effective Time, including PAA Common Units that will be subject to PAA Phantom Units as a result of the actions contemplated by Section 3.1(g)(i)(i).  As soon as practicable following the Effective Time, PAA shall file a Form S-8 registration statement with respect to the PAA Common Units available for grant and delivery under the MLP LTIP from and after the Effective Time and shall maintain the effectiveness of such registration statement (and maintain the current status of the prospectus contained therein) for so long as such units are available for grant and delivery under the MLP LTIP.  Prior to the Effective Time, PAA shall take such steps as may be reasonably requested by any party hereto to cause the acquisition of PAA Phantom Units and PAA Common Units pursuant to the Merger Transactions by each individual who is an officer or director of PAA to be exempt under Rule 16b-3 promulgated under the Exchange Act in accordance with that certain No-Action Letter dated January 12, 1999 issued by the SEC regarding such matters.

(b)                                 MLP Actions.  As soon as practicable following the Effective Time, MLP shall file a post-effective amendment to the Form S-8 registration statement filed by MLP on June 11, 2010, deregistering all Common Units thereunder.  Prior to the Effective Time, the MLP GP Board shall take such action and adopt such resolutions as are required to effectuate the treatment of the MLP Phantom Units pursuant to the terms of Section 3.1(g) of this Agreement.

(c)                                  Election Not to Adopt MLP LTIP.  Notwithstanding anything to the contrary in Section 6.16(a), the PAA Board or its Compensation Committee may, at its option, prior to the Effective Time, authorize the conversion of MLP Phantom Units into PAA Phantom Units under the PAA LTIP in accordance with Section 3.1(g)(i)(i) to be effective at the Effective Time, and may, in such event, elect either to adopt or not to adopt the MLP LTIP.  In the event that the PAA Board or its Compensation Committee elects not to adopt the MLP LTIP pursuant to this Section 6.16(c), the provisions of Section 6.16(a) shall continue to apply in full force and effect pursuant to their terms other than those provisions of Section 6.16(a) that relate to the adoption of the MLP LTIP.

Section 6.17                             Voting.  PAA covenants and agrees that, until the Effective Time or the earlier termination of this Agreement, at the MLP Meeting or any other meeting of the unitholders of the MLP, however called, PAA will vote, or cause to be voted, all MLP Common

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Units, and MLP Subordinated Units then owned beneficially or of record by it or any of its Subsidiaries, as of the record date for such meeting, in favor of the adoption and approval of this Agreement (as it may be amended or otherwise modified from time to time) and the Merger Transactions and the approval of any actions required in furtherance thereof.

ARTICLE VII
CONDITIONS TO CONSUMMATION OF THE MERGER

The obligations of each of the parties to consummate the Merger are conditioned upon the satisfaction at or prior to the Closing (or, in the case of Sections 7.2, 7.3, 7.6, 7.7 or 7.9 waiver by both MLP and PAA; or, in the case of Sections 7.4 or 7.8(a), waiver by MLP; or, in the case of Sections 7.5 or 7.8(b), waiver by PAA) of each of the following:

Section 7.1                                    Unitholder Approval.  This Agreement and the Merger Transactions shall have been approved by the affirmative vote of holders, as of the record date for the MLP Meeting, of a majority of the outstanding MLP Common Units, voting as a class, and of a majority of the outstanding MLP Subordinated Units, voting as a class (collectively, the “MLP Unitholder Approval”).