The Gorgon is a 1964 British horror film directed by Terence Fisher and starring Christopher Lee, Peter Cushing, Richard Pasco and Barbara Shelley. The screenplay was by John Gilling and Anthony Nelson Keys. It was produced by Keys for Hammer Films.

Germany 1910: The village of Vandorf has suffered seven murders in five years. Each victim has been turned to stone.

In an old millhouse within a forest, Sascha Cass tells her artist boyfriend Bruno Heitz that she is carrying his child. Wanting to stand up to his obligations, Bruno races off into the night to see Sascha's father despite her pleas for him not to go. She races after Bruno, but soon loses him in the forest. There, she finds a creature, looks into its face and dies. Upon examination of the body, Dr. Namaroff, a brain specialist at the Vandorf Medical Institution, discovers that Cass has turned to stone. Bruno is later found hanged in the forest. An inquest decides that it is a case of murder and suicide by Bruno, and Namaroff does not reveal the condition of Cass' corpse.

The villagers, feeling robbed of any vengeance, attack Bruno's father, Professor Jules Heitz. The police department's officers warn Jules to leave Vandorf, but he refuses to go until Bruno's name is cleared. Jules knows that a conspiracy of silence has been set up and that the villagers do not believe the true cause. He believes that the murders are the result of something inhuman from Ancient Mythology. Its spirit haunts Castle Borski; the Gorgon Megaera, is a creature whose face can turn human skin to stone.

Jules contacts his friend Professor Meister of Leipzig University, who is also his son Paul's tutor. Paul leaves to see Jules. That night, Jules is drawn to Borski Castle by a calling sound. There, he sees Megaera's face. He staggers back to the millhouse, and, whilst turning to stone, outlines a letter to Paul mentioning Megaera. Paul arrives and learns of Jules's death. Namaroff's assistant Carla Hoffman visits him at the millhouse and secretly reads Jules's letter. She later recites what she can remember of it to Namaroff. Warden Ratoff then reports that Martha, a violent inmate, has escaped the Institution. Namaroff reveals to Carla that Megaera's spirit exists and occasionally takes over the body of a human being.

That night, Paul is drawn outside the millhouse by a sound and glimpses upon Megaera's reflection in the garden pool. He wakes five days later in the Institution, aged by ten years. To destroy Megaera, Paul returns to the millhouse. Namaroff has Carla followed by Ratoff. That night, there is a full moon. Under it, Paul visits the graveyard and exhumes Jules's body and discovers that it is solid stone. Carla silently watches him. She eventually confides to Paul that Namaroff is in love with her and that she is terrified of him. Paul promises to take her away with him when Megaera is dead. But Carla fears it will be too late by then.

Meister arrives at the millhouse to see Paul. Meanwhile, Martha dies soon after being recaptured by Ratoff. Meister and Paul visit Inspector Kanof. They force him to reveal that Carla arrived in Vandorf as an amnesiac prior to the first murder.

Meeting in secret at Castle Borski the next morning, Carla tells Paul that she will go away with him to safety, but it must be right now. He refuses and she runs off. Paul runs after her and is attacked by a waiting Ratoff, whom Meister scares off. Meister believes that Carla becomes an amnesiac during the full moon. It is during that period that Megaera's spirit enters her body. Paul agrees with Carla that she must leave immediately and that he will follow later when the mystery is solved. Later that day, Paul cables Leipzig where Carla is supposed to have arrived by train, but there is no sign of her.