Sam breaks into the archive room of Hector Stokes' estate where she finds one file with her name and another with information about her mother's murder. Just then, the security guards come around, and Sam fights them off. After sustaining a light wound, she escapes, and hands her file to Aidan.
After losing his men, Stokes calls in a woman named Orla to take care of Sam. He wants her eliminated, but the presence of the Blank-faced Man is complicating matters. Orla shows up at Zoe's flat unexpectedly and tries to convince her that she's looking out for Sam, and she needs the Byzantium agent's help.
Jack meets with Soomro, the Pakistani minister who ran the bidding for the Khyber dam. Soomro tells Jack that while Turner did take out the whistleblower, he didn't live up to his promise of taking out Zahir as well. Soomro plans to award the bid for the dam to the Chinese. Jack recognizes that the Chinese are a front for Polyhedrus and tells the minister that he has the proof that Dr. Hill never did. If they won't award him the contract, he'll reveal the evidence and cost Polyhedrus billions.
Stephen Turner confronts Sam with the file he was handed by Inspector Everett. Sam quickly covers and denies any wrongdoing, and Stephen, increasingly suspicious of the role his father played in Lewis' death, tells her he wants to take her and Eddie and leave his father's house for good. Stephen gets Everett to admit on tape the orders that resulted in Lewis' death, then takes the evidence to the police. When Stephen goes in to meet with the local commander, he finds his father instead and is chastised for going against the family. His father informs him that Sam has been playing him the whole time.
Fowkes goes to Dave Ryder, claiming to hide from the cops after Tyrone set him up. When Dave brings him into his home, Fowkes goes about looking for the briefcase, which he believes contains the evidence that Polyhedrus fears.
Natalie Thorpe, Aidan's MI6 handler, meets with Edward Gillespie, the Under Secretary for the Ministry of Defence. She informs him that that file on Sam Hunter she'd given to her superior somehow ended up in the hands of Hector Stokes, and that she fears something called Hourglass is behind it. Thorpe realizes that Gillespie is part of the conspiracy and likely the person who passed on the material to Stokes, though he feigns total ignorance about Hourglass.
Sam traces a check Turner's company made out for Horst Goebel back to a young Pakistani girl named Noura, whom Goebel had sponsored. Sam meets with her and learns the true story of the Khyber dam: The people in Noura's village didn't want to leave their homes to make way for the dam, so Polyhedrus faked a natural disaster that killed 600 villagers. Doctors Hill and Goebel had collected evidence in the form of soil samples from the lake proving the so-called disaster was really a gas attack carried out by Polyhedrus. The evidence from the lake is in the briefcase that was delivered to Jack Turner.
Rummaging through Ryder's house, Fowkes finds the case. Ryder catches him in the act, but just as he forgives him, Tyrone shoots the older man in the head. Fowkes and Tyrone fight in Ryder's building, with Fowkes coming out on top. He grabs the briefcase and brings it to Byzantium, where it's revealed to be full of nothing but rocks. Zoe pores over old footage and realizes that the real briefcase never left the Turner house. The one given to Ryder was a decoy.
Keel confronts Sam about breaking into Stokes's house. He knows she came back to Byzantium to find out who wants her dead, but Sam still doesn't trust him. Natalie catches up with Sam and hands her the key to a safety deposit box, the contents of which will reveal Aidan's true identity.
Bingham confronts Everett after realizing that he's been working with Stephen. He has Tyrone kill the inspector.
Keel meets with Stokes, who asks him to move up their timetable and kill Jack Turner within 48 hours. The hasty action arouses Keel's suspicion that Polyhedrus is readying to kill Sam as soon as the mission is carried out.
At the Turner house, Jack asks to speak with Sam. He apologizes for the way he's treated her, and offers Sam a cup of tea--in which he's slipped in something extra.