Retired Marine sniper Bob Lee Swagger is recruited by his former commander to stop an assassination of the president; and FBI agent Nadine Memphis investigates potential assassins.

Bob Lee reaches out to Nadine while evading his pursuers; and Isaac juggles his double life while trying to find Bob Lee.

Bob Lee locates the bullet from the assassination, which leads him to a radical militia group and Isaac; and Nadine is locked in a deadly game of cat and mouse with Payne.

Bob Lee tracks down his former instructor, who he hopes will help him find the shooter; Nadine interrogates Payne; Isaac realizes that he's in over his head; and a reporter makes Julie an offer.

Bob Lee travels across the country in order to find the shooter; Julie deals with a family betrayal; Nadine contacts a Ukrainian reporter who can explain the conspiracy; and Isaac questions his allegiance.

Bob Lee and Nadine plot to secure evidence that could expose the conspiracy. Isaac searches for an exit strategy. Payne tries to flee. Julie and Mary are in danger.

Bob Lee, Julie, Nadine and Isaac work together to breach the Russian embassy, save Mary, shut down the conspiracy and prove Bob Lee innocent.