Lieutenant Brian Hawke, an officer aboard the British merchant ship "The Monsoon", volunteers for a dangerous mission to infiltrate the pirates' base at Diego Suarez on the coast of Madagascar. He is to pose as a deserter, and to make his disguise more convincing, he is given twenty lashes. When he arrives in Diego Suarez, he arouses the suspicions of the pirates, especially Captain Roc Brasiliano. Brasiliano orders him to appear before a tribunal of the Coast Captains to decide his fate. If they do not like him, he will be executed. Meanwhile, Hawke has caught the eye of Spitfire Stevens - the only woman among the Coast Captains - who inherited her position from her father.