In 1940, the Central American cocoa plantation owned by American Joan Grant (Lucille Ball) needs protection from bandits led by El Vengador (John Eldredge). She asks the Marines stationed nearby under the command of Colonel Hill (Paul Harvey) for help. Lieutenants Danny Darrick (Richard Dix) and Jim Malone (Chester Morris) fly a mission to seek out the outlaws. Although they have orders to protect her, both men vie for Joan's affection.