Having apparently committed suicide from ingesting poison in an earlier adventure, but merely in a state of cataleptic suspension induced by a secret potion, the nefarious Chinese physician is declared dead by Inspector Nayland Smith. Having sworn vengeance on the English families responsible for the death of his wife and son in the Boxer Rebellion, Fu goes to an English estate of the Bartleys, where their nephew, Jack Petrie, is about to marry Lia Eltham: Fai Lu, Lia's Chinese servant, dies mysteriously, and Lia and Lady Agatha are abducted. Fu requests that Jack appear on the moors to save Lia, and Smith, disguised as Jack, attempts the mission and is taken to a deserted dyeworks via airplane. Fu escapes the police, though paralyzed by a bullet wound, and forces Jack to operate on him while Lia is put into a trance. Fu bargains with Smith and his detectives for his freedom but is killed in his attempt to escape.