Location Game Acquaintances Forgotten is an optional side-quest in Deus Ex: Human Revolution, with a similarly named achievement for completing it. It is given to the player by Frank Pritchard. The attacks on Sarif Industries, followed by the discovery of the backdoor tunnel through Pritchard's firewalls being broadcasted from Derelict Row, has greatly unsettled Pritchard. He has discovered that the person who initially created the hidden backdoor was actually none other than David Sarif himself, and for security purposes thinks Jensen should investigate.