The Castle of Fu Manchu

Somewhere in the Carribean, a cruise liner hits an iceberg. It soon emerges that the iceberg was created by another diabolical invention of Fu Manchu (Christopher Lee) who informs the rulers of the world that they must submit to his demands before he uses the weapons again. Teaming with an Opium dealer, Fu Manchu's men capture a castle full of opium which is turns out is essential to their scheme. Meanwhile, Nayland Smith (Richard Greene) and Dr. Petrie head to Istanbul to find and stop Fu Manchu... (official distributor synopsis)