In 1924, Fu Manchu, his army of henchmen and his vicious daughter Lin Tang are kidnapping the daughters of prominent scientists and taking them to his remote island, where he demands that the fathers help him to build a device that transmits blast waves through a radio transmitter, which he intends to use to take over the world. He plans to keep (even wed) the girls in question. But Fu's archenemy, Nayland Smith of Scotland Yard, is determined not to let that happen.