Night of the Demon

In England, Professor Harrington pleads with his rival, Dr. Julian Carswell, to lift the curse that he put on Harrington. In return, Harrington promises to stop investigating Karswell's witchcraft activities. After learning that the parchment he gave to Harrington has been destroyed, Karswell promises to do everything in his power. When Harrington drives up to the house, he notices a giant demon above the trees, crashes into power lines and is killed by an electric shock.

Dr. John Holden arrives in the UK to attend a convention at which Harrington intended to expose Carswell. He is informed that the only link between Harrington's death and Carswell is the suspect in the murder of another man, Rand Hobart, who fell into a catatonic stupor. While Harrington's staff are considering the possibility of supernatural forces, Holden rejects such an option.

Holden meets Carswell in the reading room of the British Museum. He calls to stop the exposure and threatens the professor, while imperceptibly placing a parchment with runic inscriptions on it. At Harrington's funeral, Holden meets the deceased's niece Joanna. She gives him Harrington's diary, in which her uncle details his fear of Karswell's supernatural powers. Holden is still skeptical, but the next day he goes with Joanna to the Karswell mansion. Suddenly, a strong hurricane begins, and Karswell claims that he caused the bad weather with a spell. Holden takes this information skeptically and makes fun of him, after which Carswell declares that Holden will die in three days.

Holden visits Hobart's family to get permission to hypnotize him and learn about the death he is accused of. The mother agrees and says that their family is very religious. When Holden is about to leave, a parchment planted by Carswell falls out of his wallet. Seeing this, Hobart's family gets scared and declares Holden "the chosen one". Later, Holden compares the runes on the parchment with the signs inscribed on one of the stones at Stonehenge.

Joanna brings Holden to a seance, where they were invited by Carswell's mother. The medium claims to be possessed by the spirit of Harrington, and says that Carswell has the key to the cipher of the witchbook, from which he drew his knowledge of the supernatural. Holden leaves, deeming the session nonsense, but Joanna says that she intends to find this key, and they go together to the Karswell mansion. Holden sneaks into the house while the girl is waiting outside. Inside, he is attacked by a cat, which suddenly turns into a panther. Holden is saved from the predator by Karswell, who says that he was waiting for him and specially left the witch guard. Holden leaves and, contrary to Carswell's warning, walks through the woods. There, for the first time, he sees a cloud of smoke and fire chasing him – a demon appeared from the same cloud, which caused Harrington's death.

Under hypnosis, Hobart informs Holden that according to the faith held by his family, he was "chosen" to die, since it was he who was given the runic parchment. But he was cowardly and escaped death by handing the parchment to another person. When Holden shows Hobart a piece of paper covered with runes that he received from Karswell, he recognizes it and decides that the professor is trying to give it to him. Hobart becomes hysterical and jumps out of the window, crashing to his death.

Holden finds out that Carswell is going by train to Southampton, and follows him. Already on the train, he discovers that Karswell has kidnapped and hypnotized Joanna. The time of Holden's death predicted by Carswell is approaching. The train stops at the station and Carswell tries to leave. Holden manages to slip the parchment into his coat pocket, and when Carswell discovers it, it flies out of his hand and the wind drives him along the tracks. Karswell runs along the rails, but when he finally catches up with the parchment, it ignites. A huge demon appears from the clouds of smoke and fire and attacks Karswell. Soon his corpse is found near the tracks, and the police decide that he was hit by a train. Holden, instead of examining the body, leaves with Joanna.