Dr. Fu-Manchu, the terrorizing and macabre master of a secretive Oriental organization, is dedicated to conquering the world. Fu-Manchu's greatest nemesis, British investigator Nayland Smith, is one of the few people who can meet Fu-Manchu's gaze without falling under his hypnotic power. It is up to Smith and his faithful companion, Dr. Petrie, to foil Dr. Fu-Manchu's diabolical plot.
In The Insidious Dr. Fu-Manchu, the lethal "Zayat Kiss," a red mark resembling the imprint of painted lips, is found among cocaine needle tracks on the dead body of Sir Chrichton Davey. The power of Fu-Manchu is far reaching as he employs a giant poisonous centipede, deadly toadstools and lethal green mists to murder and kidnap the great minds of the West. Is the beautiful Karamaneh the key to uncovering the evil Doctor's lair, or is she a pawn leading Smith and Petrie to their deaths?