Gunfighter Chuka (Rod Taylor) escorts the passengers of a broken-down stagecoach to Fort Clandennon, a remote Army outpost run by stern British Col. Stuart Valois (John Mills). One of the passengers is Veronica Kleits (Luciana Paluzzi), a widowed Mexican aristocrat who loved Chuka but could not marry him because of the gap between their social classes. As Arapaho Indians encircle the fort, Colonel Valois prepares for a desperate last stand to redeem himself for an act of wartime cowardice.