Thunderbolt (Clint Eastwood) is a former thief who was once a master of his profession, but he's about to reenter the criminal world with a new partner: Lightfoot (Jeff Bridges), a brash young drifter whose energy and exuberance give the veteran a new outlook on life. Their target: the seemingly impenetrable Montana Armored Depository. This is the first feature film by the great Michael Cimino (The Deer Hunter).

At the height of the frontier era, a locomotive races through the Rocky Mountains on a classified mission. But one by one, the passengers are murdered! Their only hope is John Deakin (Charles Bronson), a mysterious prisoner-in-transit who must fight for his life, and the lives of everyone on the train.