Secret Service agent Mike Banning (Gerard Butler) undergoes training at a military facility in Virginia, owned by his friend and Army Ranger teammate Wade Jennings (Danny Huston), who is now CEO of the private military company Salient Global. He is recommended for the position of Secret Service Director by President Allan Trumbull (Morgan Freeman), to replace retiring Director David Gentry (Lance Reddick), but hides the fact that he suffers from migraines and insomnia and takes painkillers to cope with chronic back pain.
While Trumbull is on a private fishing trip at Queen’s Lake in Williamsburg, Virginia, a swarm of armed drones attack his protection detail, with only Banning surviving and saving the president. Both men are incapacitated, but Banning recovers while Trumbull is left in a coma. Vice President Martin Kirby (Tim Blake Nelson) is sworn in as acting president. FBI special agent Helen Thompson (Jada Pinkett Smith) is presented with evidence that Banning may be implicated in the attack, after her team locates the van used to transport the drones and find it containing traces of Banning’s hair and DNA, leading to his arrest. En route to a detention facility, Banning’s transport is ambushed. He escapes after killing the assailants and unmasking them as mercenaries from Salient Global with whom he partook in the training exercise. Realizing that Jennings betrayed and framed him, he calls his wife Leah (Piper Perabo), letting her know he is alive and determined to expose the real perpetrator. The call alerts Thompson to Banning’s location, leading to a car chase by numerous police officers. However, Banning manages to escape again to his father’s cabin in the backwoods of West Virginia.
Kirby reveals to the press that Banning is responsible for the assassination attempt with support from the Russian government. Banning and his father Clay (Nick Nolte) observe Salient mercenaries approaching the house on surveillance cameras. Clay detonates multiple explosives around the perimeter, killing the would-be attackers as he and Banning escape. Banning reveals to Clay that he has a wife and daughter. Leah and her daughter are on the verge of being kidnapped by Salients when Clay saves them. Finding the bodies of Jennings’ gunmen lined up against Clay’s cabin, Thompson deduces that Banning may have been set up after all. Trumbull awakens from his coma and Kirby is revealed to secretly be collaborating with Jennings; Kirby plans to retaliate for the President’s “attempted assassination” by declaring war on Russia. Thompson and another agent meet Jennings on an airfield, but Jennings kills both FBI agents.
Banning reaches the hospital and gives himself up, but Trumbull orders his release. Banning leads Trumbull to safety with help from Gentry and other loyal agents as Jennings destroys the hospital’s ICU by increasing the oxygen & nitrogen supply to unstable levels, causing a massive explosion that levels the hospital. Banning hides Trumbull and Gentry as Jennings’ men pursue them. In an extended gun battle, Salient Global forces start off with the advantage, but Banning turns the tide and eventually the mercenaries are in retreat. A handful of them, led by Jennings, are gathering on the rooftop to escape in a helicopter, when Banning blows up the helicopter with a grenade launcher. Only Jennings survives the explosion, which leaves the principals to fight it out. Jennings and Banning engage in hand-to-hand combat ending with Banning fatally stabbing Jennings. The remainder of Jennings’ men are either killed in the firefight or confronted and arrested by U.S. federal law enforcement officers.
Banning is exonerated while Trumbull and a visibly-wounded Gentry arrest Kirby for treason, revealing that Jennings had kept detailed records of Kirby’s involvement, as an insurance policy, and uncovered by Thompson. Gentry is given the privilege of perp-walking the Vice President through the press. Clay decides to live with Banning and his family. Feeling guilty over his failure to protect Trumbull and concealing his ailments, Banning offers his resignation, but Trumbull forgives him and offers Banning the promotion to Director of the Secret Service, which he proudly accepts.