CIA analyst Joe Turner finds a clue that sheds new light on a failed biological attack at a US football stadium. The evidence threatens Joe's life along with everyone he cares about.

Joe escapes Joubert and Deacon and calls Bob Partridge to bring him in. Sam Barber wrestles with his betrayal of Joe, which causes his partners to doubt his loyalty.

News of the massacre at IEP spreads. Bob seeks an ally after learning that he must remove himself from the operation to find Joe. Reuel questions Mae's knowledge of Sam's recent behavior.

With the task force closing in, Joe is forced to flee with Kathy. Marty suspects there may be a mole on her team. Reuel grows increasingly concerned about Bob's loyalty. Joe's search for answers leads him to two important people from his past.

Reuel and Marty hope that Caleb Woolf will be the key to Joe's capture. Bob attempts to extract information from Joubert. In Riyadh, a plan is put into motion.

Mae is tortured by lingering questions surrounding her husband's passing. Caleb tells Joe about his CIA source. Joubert and Boyd cross paths at Kathy's house and make a critical discovery.

Another person close to Joe is found dead. Bob shares his theory about the IEP attack with Sharla. Iris gives Mae information that puts both of their lives in jeopardy.

Joe continues piecing evidence together. Bob deploys a capture mission without Reuel's approval. Mae receives intel from Iris about Sam and Elden. Nathan confronts Gareth.

Deacon's traumatic past comes into focus. Sharla pursues Joubert. Mae makes a terrifying discovery. After the location of the plot is uncovered, Bob considers his options and Joe compels Janice and Caleb to help him.

Joe's morality is put to the ultimate test as he attempts to stop the plague from being released.