Acquaintances Forgotten

Forgotten Acquaintances is an optional side-quest in Deus Ex: Human Revolution, though it is perhaps the most plot-relevant of them all in the game. It is given to the player by Frank Pritchard.

Introduction
The attacks on Sarif Industries buildings, followed by the discovery of the backdoor tunnel leading right past 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.

Overview
This is a two-part quest taking place entirely in Detroit. The first part takes place right after Jensen returns to Sarif Industries from the Highland Park FEMA facility. Pritchard will be in Jensen's office and demands to see him, and there he will give him the quest. He wants Jensen, as Sarif's trusted security man, to confront Sarif and ascertain the purpose of this hidden tunnel. Jensen must then engage Sarif in a dialogue challenge to get him to reveal his secrets, in which case he will learn that Sarif created the tunnel originally to communicate covertly with a private detective that he hired to dig up Jensen's past.

The second part takes place after Jensen returns to Detroit from the Picus building. Pritchard will inform Jensen that he has obtained the identity and location of Sarif's private investigator, one Brent Radford. Jensen must then find and confront this Radford to obtain the secrets of his own past.

Walkthrough
Jensen must meet with Pritchard in his office first, before going up to Sarif's penthouse after coming back from the FEMA facility. Then Sarif will most likely be the second dialogue challenge the player attempts, after Haas.

Jensen can either appease the confident, assertive CEO by insisting he needs the information to help his boss, put the focus directly on the backdoor tunnel and claim it as a dire security matter, or go on the defensive, asserting that with his service (especially on this particular day), he deserves to know and Sarif should not hide any security secrets from him. With the Social Enhancer augmentation, Jensen can also threaten to quit, alarming Sarif's alpha personality. If successful Sarif will spill everything and even forward the emails from the private investigator to Jensen.

This part of the quest is over for now, though the player will learn some intriguing details from the private detective's emails. But once the player returns to Detroit from meeting with Eliza, Pritchard will contact Jensen and set off the second phase of the quest.

Upon arriving at Radford's apartment however, Jensen will find an armed suit that must be dealt with, and a severely wounded Radford. Radford will refuse to speak with Jensen until Jensen retrieves a trauma kit in the closet and give Radford a shot of morphine. It turns out the detective is another purist who despises augmentation, and though he's ultimately willing to cooperate, he has nothing but disdain for the "robot" Jensen.

Radford will direct Jensen to his storage locker, and to find a woman named Michelle Walthers for further answers. Then he will ask Jensen to euthanize him - he recognizes his wound is serious and even if he survives, he will likely become a paraplegic. Refusing to either get augmented as he despises augmentation or live for the rest of his life in a wheelchair, Radford would rather die whole and needs Jensen to do it as he can't do it himself.

Jensen can either bully Radford into living, convince him that life would still be worth living, or convince him that augmentation isn't that bad and even the robotic Jensen is still human. Keeping Radford alive at this point is strictly optional.

Radford's security locker is in the alley near the police station. Several armed men in black will be there and must be dealt with, however police are nearby as there has been rioting in Detroit, and if they hear any gunfire they will become hostile. At this point the quest comes to an end unless Jensen can hack the safe in the locker, where he retrieves some notes and a few photographs of his baby self.

Next Jensen must track down the mysterious Michelle Walthers. Upon reaching her apartment, he finds that she is a nice but senile elderly woman, who mistakes the heavily augmented Jensen for a Meals on Wheels deliveryman. Jensen will play nice and pretend that he is talking about someone else, but he will need the baby photos to proceed.

Walthers then proceeds to tell Jensen, still mistaking him for a delivery boy, about his own past and how she saved his life when he was an infant. At one point Jensen will face a dialogue challenge and should sweet talk the kind old lady for more information. Eventually he will get all he can and then can just leave her apartment to complete the quest.