A classic action-filled John Wayne western is set into motion with a spectacular robbery of a Union pay train by Confederate guerrillas. The train's colonel (Wayne) jails the enemy leaders (Jorge Rivero, Chris Mitchum) but the three men later become friends when the war ends. Together they seek the Union traitors responsible for a string of Confederate train robberies, a mission that culminates in a rousing shoot-'em-up finale.

Howard Hawks's final film once again teams him with John Wayne, with a script by Leigh Brackett (who also wrote his EL DORADO and RIO BRAVO). The time is just after the end of the Civil War. Wayne is Union Colonel Cord McNally, who is teamed with two Confederate soldiers he captured during the war in order to take down a thieving bootlegger. Their travels take them to a small town being held in terror by an evil Sheriff. McNally and his crew decide to help the townspeople with their own brand of justice. With a considerable amount of humor and Hawks's reliable formula in which a motley band of men unite for a common cause, RIO LOBO is a fitting conclusion to both his western trilogy and a distinguished career.