In this adaptation of Gaston Leroux's novel, a musician has to retire from the opera but commits murders and hangs on behind the scenes to help a young singer.
Anatole Garron (Nelson Eddy) sings opera, and violinist Erique Claudin (Claude Rains) is upset that Christine Dubois (Susanna Foster) missed the curtain call. Inspector Raoul D'Aubert (Edgar Barrier) asks Christine to give up opera, but she won't. The director urges her to be a singer, but he dismisses Claudin because of his hand. Claudin's landlady demands he pay his rent. Claudin tells Christine's voice teacher that he can't pay for her lessons for a while. Claudin has written a concerto, which is rejected. When he hears Franz Liszt (Fritz Lieber) playing it, he accuses the publisher Pleyel of stealing it and strangles him. His servant throws acid on Claudine's face.
Claudin hides under the street in the sewers. He is wanted for murder. The opera is missing the master key. Christine sings a lullaby for Anatole. Raoul asks Christine about Claudin and shows the statuette of her he found in Claudin's room. Anatole says he made it. In her dressing room Christine hears the voice of Claudin saying he will help her. Anatole tells her the same thing. Anatole and Biancarolli (Jane Farrar) sing on stage, but she comes off and collapses. A doctor says she was drugged, and she accuses Anatole. Christine replaces her and sings well.
Raoul questions Anatole and his accuser, Biancarolli, who demands a new understudy and no publicity for Christine. Claudin in a mask warns Biancarolli to leave Paris, then murders her and her maid. Claudin climbs up a ladder and is chased by Anatole. Raoul says someone else must sing, but Anatole wants Christine to sing. Anatole asks Liszt to play Claudin's concerto. Raoul won't let Christine sing. Masked Claudin kills a masked extra and goes on stage. Raoul finds the corpse and removes masks. Anatole sings, and Claudin saws the chandelier chain. As a soprano sings, the chandelier falls. In the chaos Claudin leads Christine away to the sewer and says she can't go back. Raoul tells Anatole that Christine disappeared. They search as Liszt plays the concerto. Claudin hears it and plays piano in the sewer. He gets Christine to sing, and she tears off his mask, revealing his scarred face. Raoul's gun goes off, causing a cave-in that buries Claudin. Raoul and Anatole rescue Christine, who says she pitied Claudin. In the final scene Christine performs well and goes out to her fans, leaving Anatole and Raoul to dine together.
The peculiar horror of this story is that a fine musician
who is secretly and selflessly helping someone commits several
murders to further these altruistic purposes. Although the novel
is much older, this mirrors how Nazis could love great music and
still kill ruthlessly.