USMC Force Recon Scout Sniper GySgt Bob Lee Swagger and his spotter Donnie Fenn provide armed overwatch for a mission in Ethiopia. The mission goes awry when an enemy militia assaults Swagger and Fenn's position with helicopter support. The CIA officer supervising the operation burns the mission, resulting in Fenn's death.
Three years later, Swagger is retired and lives with his dog in the Wind River Range. Swagger is approached by U.S. Army Colonel Isaac Johnson and his associates, Payne and Dobbler, to enlist his aid in thwarting a potential assassination attempt on the President during a public speaking event. Reluctantly, Swagger agrees to help. He assesses the only viable location is Philadelphia. On the day of the speech, Swagger accompanies Johnson to an overwatch position. The shot is made but is revealed to be a setup: the President's guest, Ethiopian Archbishop Desmond Mutumbo, is killed, and a Philadelphia police officer, on Johnson's payroll, shoots Swagger. Swagger escapes, disarms rookie FBI Special Agent Nick Memphis, and flees into the Delaware River.
Swagger travels to Kentucky and meets Fenn's widow, Sarah, who treats his injuries. Using Memphis, who was skeptical of the shooting, as bait, Sarah and Swagger feed him information, which he uses to investigate the shooting to force Johnson out of hiding. Suspecting they may be compromised, Johnson orders his men to capture Memphis and kill him. Before they can kill Memphis, however, they are killed by Swagger. Swagger releases Memphis and requests his help bringing down Johnson.
The two travel to Tennessee and meet with firearms expert Mr. Rate, who explains paper patching. Rate deduces that the wheelchair-bound Serbian sniper Mikhaylo Sczerbiak would be the only other sniper alive capable of making such a shot. Swagger concludes that he unwittingly conducted Sczerbiak's recon to ensure the assassination's success, and he and Memphis travel to Virginia to confront him. At the same time, Sarah's connection to Swagger is uncovered, and Johnson orders Payne to abduct her to be used as leverage.
Swagger and Memphis infiltrate Sczerbiak's estate, where the latter reveals that Johnson works for Montana Senator Charles Meachum on behalf of oil conglomerates exploiting developing nations for profit. Sczerbiak confesses that, acting on Johnson's orders, he assassinated Mutumbo to prevent information about crimes against humanity carried out by Johnson's mercenaries from going public, which include the massacre of a northern Ethiopian village on the Eritrea–Ethiopia border. Sczerbiak informs Swagger that he and Fenn had unknowingly covered the retreat of the contractors who carried out that mission and were supposed to be killed to cover it up. Upon revealing Sarah's abduction, he commits suicide. Swagger records the confession, escapes with Memphis, and kills the mercenaries sent to eliminate them. The pair escape to Montana, tip off the FBI, and arrange a meeting with Meachum and Johnson.
Johnson, Meachum, and Payne arrive, with Sarah held at gunpoint. With Memphis acting as a decoy, Swagger eliminates Johnson's counter-snipers and disarms Payne, whom Sarah kills shortly after. With Sczerbiak's recorded confession in hand, Swagger and Memphis confront the pair.
Meachum cryptically implies he is not the only politician who works for the oil companies. Deducing that the proof will get them killed, Swagger destroys the recording as the FBI arrive to take him into custody. He is granted an audience with US Attorney General Russert. Swagger asks if anyone has touched his rifle upon confiscating it from the crime scene. The moment Russert confirms that no one has tampered with his rifle, with Memphis' help, Swagger proves that his rifle was not used to take the shot that killed the Ethiopian Archbishop by taking a live sniper round secretly given to him by Memphis and trying to fire it at Johnson; but it doesn’t shoot. Swagger reveals that every time he leaves his rifles unattended at home, he removes the original firing pins and switches them with almost similar ones that need a micrometer to determine that they're not the right firing pins, making his rifles useless to other people. Memphis provides evidence to Russert cataloging Johnson's involvement in the humanitarian crimes carried out by Johnson's mercenaries. Russert laments that Johnson's crimes are outside US jurisdiction and beyond their control. Privately, Russert confides in Swagger that extrajudicial measures may be necessary to end the corruption, and orders Swagger's release.
Sometime later, Meachum, Johnson, and their associates discuss an operation in Ecuador, which is cut short when Swagger kills all of them. He ruptures the gas line, frames Johnson by putting a gun near him and flees as the house is destroyed in a massive gas explosion. Swagger returns to Sarah in a waiting car, and the two drive off.
Cast
- Mark Wahlberg as Gunnery Sergeant Bob Lee Swagger
- Michael Peña as FBI Special Agent Nick Memphis
- Danny Glover as Colonel Isaac Johnson
- Kate Mara as Sarah Fenn
- Elias Koteas as Jack Payne
- Rhona Mitra as FBI Special Agent Alourdes Galindo
- Jonathan Walker as Louis Dobbler, Meachum's aide
- Louis Ferreira as FBI Assistant Special Agent-In-Charge Howard Purnell
- Tate Donovan as FBI Special Agent Russ Turner
- Rade Šerbedžija as Mikhayo Sczerbiak / Michael Sandor
- Alan C. Peterson as Philadelphia Police Department Officer Stanley Timmons
- Ned Beatty as Senator Charles F. Meachum
- Lane Garrison as Lance Corporal Donnie Fenn
- Brian Markinson as Attorney General Russert
- Levon Helm as Mr. Rate
