Supercriminal Fu Manchu plots to freeze the world's oceans with a diabolical new device. With his evil daughter, Lin Tang, his army of dacoits, and the help of the local crime organization led by Omar Pasha (whom Fu Manchu doublecrosses), Fu Manchu takes over the governor's castle in Istanbul which has a massive Opium reserve, to control the largest opium port in Anatolia, a fuel for his machine. Fu Manchu needs the help of an intelligent scientist with an ailing heart whom he has imprisoned. In order to keep the scientist alive he kidnaps a doctor and his wife to give the scientist a heart transplant from one of his obedient servants. Opposing him from Britain's Interpol, is his nemesis Nayland Smith and Dr. Petrie.
Question: What does Fu Manchu take over?, Answer: The governor's castle. Question: What fuels the machine?, Answer: Opium. Question: What is FU Manchu's plan?, Answer: To freeze the oceans.