Joe is traveling in Europe when he is approached by a Russian agent, who says he can identify a mole within the CIA in exchange for protection. Joe begins to realize that escaping his old life may be impossible.
Joe is lured back into the danger zone when he suspects that Bob's killer and mole may be the same person.
Reuel receives a night-time visit and realizes he has landed in the center of an unexpected conflict. Kat defies her own judgment while helping an old friend.
Joe remains doubtful that Gordon is guilty, so continues his investigation in an attempt to find alternate possibilities.
While Gordon is interrogated by the counterintelligence unit, Joe follows up on some other leads. He plans to find out who rented the ambulance that was used in the attack on him and Vasili.
Tracy and Mae decide to disappear for a while; Joe has finally learned of Vasili's whereabouts, and is aiming for a reunion.
Kat is witness to Volk taking the law into his own hands; Mae's discussions with Senator Thrush have unintended consequences.
Joe runs out of options and is forced to put his loved ones at great risk. Meanwhile, Mae makes tough demands on Reuel.
Joe uncovers the traitor's identity; an old adversary pays Reuel a visit; Kat must decide where her loyalties lie.
After low-level CIA analyst Joe Turner returns from lunch to discover that everyone in his office has been killed, he goes on the run trying to elude hit men and uncover the truth about who is behind the murders.
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 unanswered questions about her husband's death; Caleb tells Joe about his source; Joubert and Boyd make a discovery.
Someone close to Joe is found dead; Bob explains his theory to Sharla; Iris gives Mae potential life-threatening information.
Joe continues to put the pieces together; despite not having Reuel's approval, Bob deploys a capture mission; Mae gets intel from Iris; Gareth is confronted by Nathan.
Deacon's past comes to light; Sharla pursues Joubert; Mae makes a discovery; Bob considers his options when the plot location is revealed; Janice and Caleb help Joe.
Joe tries to stop the plague from being released.