AllMovie

Rescued by the Hong Kong police from his water grave inside the wooden box, Smilin' Jack (Tom Brown) learns that all the members of the Black Dragon spy organization have been rounded up -- except the leader, Nazi operative Fraulein Von Teufel (Rose Hobart) and three other Germans. In her usual disguise of foreign correspondent Gertrude Muller, Fraulein von Teufel is once again present at the press conference where Mah Ling (Cyril Delevanti) is presumed to divulge the secret passage from China to India. The exasperating governor of Mandon once again delays the disclosure by requesting that the Americans cosign along with the Chinese and the British High Commission, lest the passage will remain open after the war. The signing of the final document is therefore moved to Honolulu and all the interested parties leave Hong Kong on a clipper bound for Hawaii -- including the undercover Fraulein Von Teufel and her three German operatives (Paul Bryar, Norma Drury, and Grace Cunard), who are planning to overtake the aircraft. The plot fails, however, and Jack is soon questioning Sanson (Alex Havier), Fraulein Von Teufel's one Asian cohort, who is promptly killed by one of the Fraulein's poisoned darts. Just then, the clipper is fired at from a Japanese submarine and crashes into the ocean.