You need to recruit 'arcade gannon' as a companion, he is found at the 'ol mormon fort' in freeside. After you do this you must take him to certain to certain points in the game which will remind him of his days in the enclave. Eg the crashed vertibird, reppconn headquarters. Note that when you take him there he will make a comment and open a dialogue conversation. Every time you get him to do this you earn a trust point , and you need 5 trust points for him to trust you and offer you the needed quest 'for aund lang syne'. Other places to earn points are taking him to dr Thomas hildern at camp mccaran. After simply saying hello to hildern then good bye , Arcade Gannon will open another dialogue conversation. Another place is Ceasers fort , soon as you enter the fort he will ask why we are here, replying with lets just here him out will earn you a point. After completing the quest 'The white wash' , if you blamed the death of corporal white on the Scorpion gang , you will get another trust point. Lastly make a good impression on the followers of the apocolypse by doing tasks and he will trust you enough to give you his side quest 'for auld Lang syne' and you can take it from there :)
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