Terrorized by a gang of thugs, the inhabitants of the town of Warlock decide to hire the famous gun-man Clay Blaisdell (Fonda), to act as marshal. Blaisdell arrives, accompanied by gambler Tom Morgan (Quinn), his devoted friend. When some of the townspeople, suspicious of Blaidsell, hire reformed thug Johnny Gannon (Widmark) as the official Sheriff, the town becomes embroiled in a power struggle between two men of dubious morality.

