The story, set during the Mexican revolution of 1866, casts Cooper and Lancaster as Ben Trane and Joe Erin, two rival soldiers of fortune who team to fight for the highest bidder. The two men come to loggerheads when Trane's sweetheart Nina begs them to fight on the side of the rebels, while the wealthy Marquis de Labodere implores them to offer their services to Emperor Maximillian. Though they still haven't taken sides, Trane and Erin agree to escort the aristocratic Countess Marie Duvarre (Danielle Darrieux) through hostile territory to Vera Cruz. It soon develops that the Countess is transporting a gold shipment to the Emperor's armies. Hardly the most patriotic of souls, she offers to split the gold with Trane and Erin, but they steal it for themselves instead. It takes a while (and several bloody armed confrontations) before the two protagonists do The Right Thing.