Mark Wahlberg stars as Bob Lee Swagger, a former Marine scout sniper and disgruntled American hero who thought he had walked away from the job forever after a devastating betrayal. Now, despite having sequestered himself in a stunning but remote mountain hideaway, Bob is approached by retired Colonel Isaac Johnson (Danny Glover), who tells him the country desperately needs him. As Johnson tells it, an assassination attempt on the President of the United States is imminent and only Swagger's lethal skills and savvy expertise in long range ballistics can halt the threat.

Swagger reluctantly agrees one last time to serve his country - but what he doesn't know is that the entire mission is a set-up by a dark government cabal with its own agenda. By the time Swagger realises the event has been rigged, it's too late. Suddenly, he finds himself in the headlines as the lone gunman who tried to shoot the President. Hunted at every turn, with nowhere to hide and no one to help him except a mystified woman he's just met (Kate Mara) and a novice FBI agent risking his career (Michael Peña), Swagger is in a desperate battle which will put everything he knows to the test. The clock is ticking as he tries to figure out who the real hit men are before they hit him. But Swagger soon realises that even more than his own survival is at stake - because he's about to lift the veil off a devastating conspiracy at the very heart of American power.