Brian Hawke is a British navy officer who pretends to be a deserter in order to penetrate a well-defended pirate stronghold on Madagascar. Brian is after a map of the harbor fortifications so that it can be successfully taken by the British navy. Once inside the port, Brian meets the pirate captains, including "Spitfire" Stevens and Roc Brasiliano. Brasiliano is after Stevens, who has the map, but she swoons over Brian. Brian and Brasiliano capture and burn a ship carrying Princess Patma, daughter of the Great Mogul, and her governess, Molvina MacGregor. Brian saves the Princess from the burning ship and she falls for him, too.