Sheila suspects that Terry has been drugged when he blankly asks for the real sword and mask, but she and Von Berg still go with him and are captured by Manchu's men. Soon Terry, under the influence of the drug, goes to Sheila. Manchu prepares the serum, derived from various reptiles and deadly insects, and tells Terry that it is the smallest dose, so that he will be himself again for Fah Lo See. After Manchu discovers Smith, Smith demands the release of Terry just as Terry is about to be injected by Manchu with a serum that will make him totally subject to the doctor's will. Smith follows the man and finds the secret entrance to Manchu's headquarters. Smith tells his colleague, Von Berg, that he must go away, then enters an opium den, where he sees a man with the Tattoo of Manchu on his shoulder. Manchu then has Sir Lionel's body delivered to the expedition's compound and Smith sadly reveals that he had made the phony relics to fool Manchu. She wants to make love to him later, but is stopped by Manchu, who has other things in mind for Terry.
Fah Lo See, who is attracted to Terry, orders her father's men to whip him when the sword turns out not to be geniune. Though Terry knows it is foolish, he agrees to go to Manchu's headquarters, carrying the sword and mask. The next day, Terrence Granville, Sheila's fiancé, finds a human hand wearing Sir Lionel's ring, after which one of Manchu's underlings invites him to meet Manchu. That night, expedition member McLeod is killed by a dagger thrown through a window. When the group meets up with Smith, he warns them that Manchu may strike at any moment, hoping to gain possession of the sword and mask of Genghis Kahn, which they found in the tomb. While Sir Lionel then undergoes Manchu's fiendish "torture of the bell," Sheila and the men of the expedition find the tomb and unlock its doors, despite a warning of a terrible curse. Meanwhile, at Manchu's headquarters in the Far East, the doctor tries to cajole and bribe Sir Lionel to reveal the secret, and even offers him his daughter, Fah Lo See, but Sir Lionel refuses. When Sir Lionel's daughter Sheila hears of her father's capture, she tells Smith that she plans to search for the tomb herself.
Just after Sir Lionel explains the expedition to his colleagues at the British Museum, however, he is kidnapped by Manchu's emissaries. Fu Manchu, who will use its contents for his own evil purposes. Nayland Smith begs his friend, Sir Lionel Barton, to find the tomb of Genghis Kahn before it is discovered by Chinese scientist Dr.