A Nazi submarine lurks in the treacherous waters of a fog-shrouded reef, transferring stolen torpedoes from a hidden island. Joe Morgan, an exiled American thief, betrays his homeland by providing these munitions to the Germans. When chance reunites him with Jim Taggart, an ex-police officer with a score to settle, their old rivalry is re-ignited. Determined to bring the traitorous criminal to justice, Taggart pursues Morgan through the south seas underworld, encountering sailors without allegiances, dangerous fugitives, and a brothel full of submissive native girls all living under the constant threat of a Nazi invasion.