Supercriminal Dr. 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 Dr. Fu Manchu double-crosses), Dr. Fu Manchu takes over the governor's castle in Istanbul, which has a massive opium reserve, to control the largest opium port in Anatolia, since the drug is an important ingredient for the fuel for his machine. Dr. 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 branch of Interpol are his nemeses, Nayland Smith and Dr. Petrie.