Die, Monster, Die! is a 1965 British-American horror film directed by Daniel Haller and starring Boris Karloff and Nick Adams. The film is loosely based on the H.P. Lovecraft story "The Colour Out of Space".
The film follows the story of a young man named Stephen Reinhart (Nick Adams), who travels to the remote estate of his fiancé Susan Witley (Suzan Farmer), located in the English countryside. Upon arriving, Reinhart discovers that Susan's father Nahum (Boris Karloff) is conducting mysterious experiments in his greenhouse. Susan's mother has already died from the effects of the radiation emitted by the meteorite, and the radiation has now mutated the local plant life into giant, aggressive organisms.
Nahum, who has been wheelchair-bound for some time, invites Reinhart to stay at the estate and observe his research. However, Reinhart soon realizes that something is deeply wrong with the Witley family and their experiments. He discovers a locked room in the mansion that contains the meteorite, and also finds that Susan has been affected by the radiation and is slowly transforming into a plant-like creature.
As Reinhart tries to unravel the mystery of the Witley family's experiments, Nahum becomes increasingly obsessed with the meteorite, believing it to be the key to his own immortality. In the climactic scene, Nahum takes matters into his own hands and tries to destroy the glowing object, with disastrous results.
Die, Monster, Die! is notable for being one of the first horror films to blend science fiction elements with traditional Gothic horror. It has since become a cult classic, known for its eerie atmosphere, creepy soundtrack, and memorable performances by Karloff and Adams.