Based on a novel by Maurice Renard, a psychotic surgeon transplants a murderer's hands on to the pianist husband of the woman he loves.
Yvonne Orlac (Frances Drake) acts in the theater of horrors undergoing torture. Her husband Stephen Orlac (Colin Clive) gives a piano concert. After the play Dr. Gogol (Peter Lorre) goes to Yvonne's dressingroom and says he must see her again. At her going-away party he kisses her. He buys a wax figure of her and tells the story of Galatea.
On a train a man asks for the autograph of murderer Rollo (Edward Brophy), who throws Stephen Orlac's pen into the wall. A train wreck results in Stephen's hands needing amputation. The American reporter Reagan (Ted Healy) attends the guillotining of Rollo and asks Dr. Gogol to write articles. Yvonne takes her husband to Dr. Gogol. He calls the police for Rollo's body and transplants his hands to Orlac. When he removes the bandages, Stephen says they look different. Gogol say it's because they were crushed. The rehabilitation does not enable Orlac to play piano well. Yvonne sells her jewelry, but they still owe money. Stephen throws a knife at a man collecting for the piano. Orlac argues with his step-father, who refuses to give him money. Stephen throws a knife at him and then looks at his hands.
Gogol tells Yvonne he worships her, but she is frightened by him. Reagan brings brandy to Gogol's housekeeper Francoise (May Beatty) and discovers the statue of Yvonne. Gogol tells Reagan to get out. Orlac asks Gogol about his hands, saying they want to kill. Gogol calls it "arrested wish fulfillment." Gogol tells Yvonne that Orlac must go away alone and that she must be his. She leaves in disgust. Gogol talks to himself. When Orlac's father is murdered, Orlac is suspected. Orlac is told by a man claiming to be Rollo (saying Gogol put his head back) that he has his hands and killed the jeweler. Orlac tells Yvonne, but she doesn't believe him. Police arrest Orlac for murder and find his fingerprints are the same as Rollo's. Yvonne goes to see Gogol, and the drunk Francoise thinks the statue came to life and is arrested. Gogol comes home in the Rollo disguise, laughing at how he fooled Orlac. Yvonne stands in place of the statue. Orlac tells police the story, and Reagan believes Orlac's hands are Rollo's and tells the police to go after Gogol, because he loves Orlac's wife. Gogol calls Yvonne Galatea and says he loves her. As the mad doctor is strangling her, the police break in, and Orlac throws a knife into the back of Gogol to save Yvonne.
In another story of independent medical experimentation with corpses a skillful but mad surgeon tries to compensate for being utterly foolish at attracting a woman.