Frank Horrigan (Clint Eastwood) is a Secret Service Agent who keeps thinking back to November 22, 1963, when, as a hand-picked Agent by President John F. Kennedy, he became one of the few Agents to have lost a President to an assassin when Kennedy died. Now, former C.I.A. assassin Mitch Leary (John Malkovich) is stalking the current President (Jim Curley), who is running for re-election. Mitch has spent long hours studying Horrigan, and he taunts Horrigan, telling him of his plans to kill the President. Leary plans to kill the President because Leary feels betrayed by the government. Leary was removed from the C.I.A., and the C.I.A. is now trying to have him killed. After talking to Leary, Horrigan makes sure he is assigned to Presidential protection duty, working with fellow Secret Service Agent Lilly Raines (Rene Russo). Horrigan has no intention of failing his President this time around, and he's more than willing to take a bullet. White House Chief of Staff Harry Sargent (Fred Dalton Thompson) refuses to alter the President's itinerary, while Horrigan's boss, Secret Service Director Sam Campagna (John Mahoney), is supportive of Horrigan. As the election gets closer, Horrigan begins to doubt his own abilities, especially when Horrigan's colleague Al D'Andrea (Dylan McDermott) is killed by Leary. But Horrigan may be the only one who can stop Leary.