Bob Lee Swagger and wife Julie join his former Marine unit in Germany and narrowly escape a deadly terrorist attack. FBI Agent Nadine Memphis, meanwhile, takes a job in Washington with Patricia Gregson.

Bob Lee investigates the terrorist attack that may have targeted his Marine unit. Memphis helps on the ground in Germany. Flashbacks to Afghanistan help shed light on who might be after them.

Bob Lee and Isaac must team up to escape a Mexican prison before Solotov finds them. As Nadine digs deeper into Atlas, the cover-up points back to Bob Lee's unit. Julie has problems with the law.

Bob Lee tries to draw out Solotov, but realizes he holds the upper hand; flashbacks reveal the origin of Solotov; Isaac is courted by his creator. Season Finale.