When a band of Central American outlaws led by revolutionist El Vengador raid the cocoa plantation owned by American Joan Grant, Joan turns to the United States Marines for protection. The Marines, under the command of Colonel Hill, are training at a nearby post, and the colonel assigns Lieutenant Danny Darrick and the newly arrived Lieutenant Malone to fly a reconnaissance mission to locate the bandits' hideout. Although comrades at arms, the lieutenants find themselves in competition for Joan's affections, and the appearance of Darrick's old flame, Teresa, straddles him with a definite handicap. After a night of romance, the Marines take off on their mission, but their airplane is shot down by the bandits, and they must parachute to safety. Soon after their return to the post, Joan decides to return to her plantation to retrieve the contents of the safe, and Darrick and Malone volunteer to escort her. Along the way, they find Joan's neighbor murdered and his house in flames, and Malone returns to the post to report the attack while Joan and Darrick continue to the plantation. Upon reaching Joan's plantation, they are ambushed by the bandits, who are being led by Joan's foreman, John Henderson, who has been masquerading as El Vengador. After knocking Darrick unconscious and kidnapping Joan, Henderson returns to town and sets a trap for the unwitting Marines. While the doctor confines Darrick to bed because of the blow he has suffered, Malone leads a column of Marines into Henderson's trap. Luckily, Darrick disobeys orders, borrows a plane and arrives just in time to foil Henderson's ambush and rescue Joan.