Christopher Lee returns as the super-sinister Asian genius Fu Manchu, who terrorizes the globe by threatening to freeze the world's oceans with his latest invention. Fu takes control of Istanbul in order to have access to the world's largest supply of opium, which he needs to run his evil ice-maker, and only Interpol's Dr. Nayland Smith (Richard Greene) stands in his way. With Maria Perschy, Tsai Chin; Jess Franco directs. AKA: "Assignment: Istanbul," "The Torture Chamber of Fu Manchu."