In 1547, in Spain, an Englishman named Francis Barnard (John Kerr) visits the castle of his brother-in-law Nicholas Medina (Vincent Price) to investigate his sister Elizabeth’s mysterious death. Nicholas and his sister Catherine (Cuana Anders) say she died of a rare blood disorder six months ago. But Francis is not satisfied and he vows not to leave until he learns the truth. He asks again at dinner with the family physician Doctor Leon (Anthony Carbone), who says she died of a heart-attack after a fright. Francis wants to see where she died and is taken to the castle’s torture chamber. She was obsessed with the devices there, he is told, and locked herself in the Iron Maiden. Francis finds this hard to believe.
Francis tells Catherine that Nicholas seems to show guilt feelings and Catherine talks about his traumatic childhood. Their father was the notorious Sebastian Medina of the Spanish Inquisition. As a small child, Nicholas saw him beat his brother Bartholombe with a red-hot poker and torture the boys’ mother Isabella to death. Later, Doctor Leon says that Isabella was not tortured to death but walled up and buried alive. Nicholas wonders if Elizabeth had not been buried alive herself.
Nicholas believes that his late wife’s vengeful ghost wanders the castle. Noises and strange things happen in her room, and her harpsichord plays in the middle of the night. Elizabeth’s ring is found on the keyboard. Nicholas forces Francis to open his wife’s tomb and they find her putrefied corpse twisted as if she had died trying to claw her way out of her sarcophagus. Nicholas faints. Now on the verge of insanity, Nicholas hears Elizabeth calling him. He follows her voice to her tomb. She rises from her coffin and chases him into the torture chamber, where he falls down the stairs. Doctor Leon and Elizabeth, still alive, show up. It seems that they are lovers and planned this to inherit his fortune and castle.
Doctor Leon confirms that Nicholas is mad. Elizabeth taunts him and he awakens, laughing hysterically. He believes he is Sebastian Medina and replays his mother’s and uncle’s murders. He seizes Elizabeth and Doctor Leon falls to his death in the pit. Francis follows the noises into the torture chamber and is knocked unconscious. He is strapped to a slab and a razor-sharp pendulum swings above him, coming closer with each swing. Catherine arrives just in time with a servant named Maximillian (Patrick Westwood). Struggling with Maximillian, Nicholas falls to his death and Francis is released from the torture machine, still alive. They leave and lock the room, not knowing that Elizabeth is still alive, gagged and trapped in the Iron Maiden.
The film was directed by Roger Corman and written by Richard Matheson, inspired by Edgar Allan Poe’s 1842 short story. Cinematography was by Floyd Crosby, sets designed by Daniel Haller, and the music by Les Baxter, just like House of Usher, released the previous year. Stephen King said the film was an important event in horror film. Having been so successful with House of Usher, they considered doing Masque of the Red Death, but it would have been more expensive. They did it later in the U.K., where filmmaking was cheaper.
They used the short story as the third act and made up the first two acts. Matheson’s original screenplay had a flashback to happier times but Corman cut it because he did not want pleasant times in the sunshine. His theory about Poe is that everything comes out of a dark unconscious and real life should never intrude. The film was shot in fifteen days for $300,000, according to Corman. The flashbacks were in camera-tilted monochrome. Daniel Haller searched for discarded parts of period filmsets and put them together for a cheap but atmospheric set. A pendulum was actually used by the Spanish and German Inquisitions. That much is accurate.
This one hung 35 feet in the air, was 18 feet long, swung in a 50-foot arc, and weighed more than a ton. Originally, it was wood with a rubber blade, but that didn’t work well, so they went to a sharpened steel blade and John Kerr wore a steel band across his chest so it would cut his shirt but not actually slice him up. To make him feel better, Roger Corman took his place as the thing has being hung. But they noticed that Kerr was perspiring a great deal. They removed every second frame of the film to make it seem to swing faster. The film made two million dollars and received rave reviews. It has only grown in reputation and has had a particularly powerful effect on Italian horror film.