In the wake of the explosion at Goncourt and Co., Aidan is found unconscious in the wreckage and delivered to the hospital. When he comes to and finds himself on a stretcher, he sneaks out, walking past the Blank-faced Man.
The Blank-faced Man pays a visit to Sam in the same hospital. He admits to injecting her in the eye with a sedative, but claims he did it to prove he's looking out for her, and to give her a cover story. He warns Sam her life is in danger and to trust no one. When Sam asks how she was found out in Tangier, he gives up Aidan as the source.
At the Byzantium office, Crane sits down with Aidan in a holding room and accuses him of being a mole. Aidan denies it and throws the accusation right back at him, but Keel believes it's just a stalling tactic. Left alone, Aidan takes out two guards in the holding room, then two more in the hallway. Keel and Crane have him cornered, so he shoots through the glass and jumps to the ground floor a level below.
Keel takes a meeting with George Ballard, a former colleague of his at MI6. After disagreeing over questions of ideology, Keel questions him about Sam Hunter and Hourglass but Ballard doesn't say anything.
The Goncourt blast has the desired effect, raising $30 million for Jack Turner's company through the Kismet program. Lewis, upset about his role in all of it, tells Jack he wants out. Jack's security man Bingham suggests they take him up on it.
Stephen and Eddie Turner visit "Alex" in the hospital. She tells them the doctors advised her to stay a few more hours, but as soon as they leave, she tracks down Aidan's phone and follows him to the Red Friar Hotel, his meeting point with Natalie Thorpe. Aidan tells his handler that he's been found out, and confronts her about setting up Sam in Tangier. Sam sneaks in after Natalie leaves and asks Aidan some questions of her own.
Aidan tells Sam that Ballard wants to meet her, alone, at the National Gallery. Standing in front of a painting titled, "The Ambassadors," Ballard tells her about its significance. He believes it contains coded information about the existence of a centuries-old conspiracy, Hourglass, which is determined to concentrate the world's wealth in private hands. Five centuries later, the conspirators have become five international companies set on taking out Sam. He doesn't know why they're after her, but he does know that three of the members on Byzantium's board are from Hourglass corporations. Before he can say more, Sam spots the Military Man coming after them. They rush outside, but it's too late--the Military Man shoots Ballard in the neck with a dart and kills him.
Trudie, Lewis's secretary and former lover comes to see him. Byzantium uses this information to set her up so that Turner would think hers was the face he saw in the window the night he murdered Professor Cage. Crane leaves Sam's jacket in her apartment, and Bingham takes the bait. He has Tyrone kill the man who's now Trudie's husband, then shoots her as well. Tyrone then goes to Lewis's home and kills him too.
Leaving the Gallery, Aidan comes clean to Sam. He started working for MI6 when Thorpe found out his true identity, which is not Aidan Marsh. Aidan refuses to give up his real name so as not tocompromise Sam, but she still doesn't believe she can trust him. Following up on the only lead they have, Sam and Aidan arrive at the home of Byzantium board member Hector Stokes. Outside the house, Sam spots the distinctive roofs of three Oast houses, and flashes back to her childhood. As they explore, Sam realizes that she's been there before--but they're immediately attacked by the Military Man and his thugs. The Military Man finds himself with a clear shot at Sam, but he's taken out by sniper rifle, fired from far away by the Blank-faced Man.
Keel tells Thorpe he planted money in her account, news that he'll bring to her boss's attention unless she tells him everything. Thorpe admits that she has a mole, but claims it was Hasan, which gets Aidan off the hook. Aidan turns himself in and apologizes to Crane for his false accusation.
Sam returns to the Turner home later that evening. After she puts Eddie to bed, Stephen tells her he called the hospital and found out that Sam left immediately after their visit. When he asks where she was, she avoids the question, breaks down in his arms, and brings him to bed.