Bob Lee Swagger and wife Julie join his former Marine unit in Germany and narrowly escape a deadly terrorist attack. FBI Agent Nadine Memphis takes a job in Washington with Patricia Gregson.
Bob Lee finds Isaac in Texas after an attempt on his life; Nadine learns how much influence Patricia Gregson has; Julie fights to stay strong for her family.
Bob Lee and Isaac learn the world's greatest assassin is in theUS. Flashbacks to a mission in Afghanistan reveal his identity:Solotov. Nadine comes to Texas with suspicions of a conspiracy.
Bob Lee tries to piece together Solotov's motive for targeting his unit; Nadine finds a witness to the event that set everything off; Solotov hides in plain sight.
Bob Lee tracks Solotov's money and goes up against a Mexican cartel; Nadine helps a journalist investigate a cover-up; Julie makes her frustration heard.
Bob Lee and Isaac must team up to escape a Mexican prison before Solotov finds them. As Nadine digs deeper into Atlas, the coverup points back to Bob Lee's unit. Julie has problems with the law.