The evil Dr. Fu Manchu, with the aid of his sadistic daughter Lin Tang, has set up headquarters in a "lost city" in the Amazonian jungle. He has resurrected a 500-year-old practice of using a snake bite to inject venom into women that makes them carriers of the "kiss of death". The women are immune to the effects of the venom but imparts blindness followed by death to any man kissed by one of them. Fu Manchu has captured ten women to treat with the venom so that he can send them to find his worst enemies in major cities of the world - Berlin, Paris, Tokyo. The enemy his is most anxious to get rid of is Nayland Smith, a Scotland Yard detective who has cause great problems in the past. He sends Celeste to do him in. She manages to kiss him, but it only causes blindness. The next time the moon is full, however, he will drop dead. He realizes this and engages the assistance of his friend, Dr. Petrie, to find Manchu and get the antidote. He has sent ahead his agent, Carl Jansen, disguised as an archaeologist, to ferret out any preliminary details about the location of the lost city. A portly bandit named Sancho Gomez causes trouble for the local peasants. Ursula Wagner, daughter of Professor Wagner who died in Jansen's first approach to the lost city, is a nurse that helps manage Smith's case. Jansen manages to infiltrate the lost city but is captured. Petrie and Ursula manage to keep Smith alive until the full moon has passed. Smith regains his eyesight and helps bring the lost city hideout to an end. Fu Manchu escapes vowing to return for further mischief.
—Garon Smith