Three men seek hidden loot during the Civil War.

In the Southwest during the Civil War, a cashbox containing $200,000 is stolen and hidden in an unmarked grave. Nearby, a mysterious stranger called Joe has formed an uneasy alliance with Tuco, a Mexican outlaw. To make money, Joe turns Tuco over to a series of sheriffs, collects the bounty money, then rescues the outlaw from a hanging, and the two of them share the reward. Their scheme nearly fails because of a poor shot by Joe, and Tuco decides to betray his companion. Although Joe kills the three men commissioned by Tuco to kill him, he is nonetheless captured by Tuco and dragged through the dry heat of the desert to near death. When Joe informs Tuco that he has learned the location of the $200,000, Tuco immediately gives him water and shade before they embark on a search for the cashbox. Meanwhile, Setenza, a sadistic criminal, is conducting his own search for the cashbox and has joined the Union Army to find the soldier who knows where the money is buried. Dressed in Confederate uniforms, Tuco and Joe are captured by the Union Army and brought before Setenza. Tuco, claiming to know the location of the cashbox, is brutally beaten by Setenza until he reveals that the money is hidden in a graveyard. The three men then separately head for the graveyard, each trying to dupe the others into revealing the exact gravestone under which the cashbox is buried. In a final gunfight, Joe shoots Setenza but spares Tuco and leaves him his share of the money--all the bandit has to do for the gold coins is free himself from the rope hanging around his neck. Before he rides off, however, Joe shoots through the rope, and Tuco is left in the middle of nowhere, wealthy but without a horse.