THE PLAGUE OF THE ZOMBIES

In a Cornish village in August 1860, the inhabitants of the town are dying from a mysterious plague that seems to be spreading at an accelerated rate. Even the local doctor, Peter Tompson, cannot combat the disease. Alarmed, Tompson sends for outside help from his friend and former mentor, Sir James Forbes. Accompanying Sir James is his daughter Sylvia, a childhood friend of Peter's wife, Alice. As Sir James and Sylvia arrive in the village, Sylvia deters a group of rowdy fox hunters from killing a fox. Shortly after, Sir James and Sylvia encounter a funeral procession in town, which is interrupted by the fox hunters, who come to harass Sylvia for intentionally misleading them. In the melee, the pallbearers drop the casket over the side of a bridge, revealing the corpse of John Martinus, a recently deceased man.

In an attempt to learn more about the disease, Sir James and Peter attempt to disinter the corpses that were recently buried, and are frightened upon finding the coffins empty. Meanwhile, Sylvia is harassed by the fox hunters while walking through the woods, and chased into a manor house owned by Squire Clive Hamilton. The hunters humiliate Sylvia in what appears to be pre-emptory rape, but are stopped by Squire Hamilton, who chastises them for harassing her. As Sylvia departs the house, she encounters a grey-skinned man near an abandoned tin mine headframe, and watches in horror as he throws Alice's lifeless body onto the ground. The following morning, Sylvia leads her father and Peter to the location, where they locate Alice's corpse.

Police accuse Tom, the brother of John Martinus, of killing Alice, as he was found sleeping in a drunken stupor near her body. Tom denies involvement, and claims he witnessed his deceased brother walking near the mine. An autopsy on Alice shows no signs of rigor mortis, and, even stranger, blood smeared on her face is determined to be of animal origin. Sir James notices a bandaged slash wound on her wrist, which Peter says she sustained on a piece of broken glass days before. Later that evening, Squire Hamilton pays Sylvia a visit. Purposely, Hamilton manages to shatter a wine glass, and Sylvia happens to cut her finger on one of the sharp edges of the glass. Secretly, the Squire conceals a vial of Sylvia's blood in his coat pocket and departs.

The next day, at Alice's funeral, Sylvia begins to feel faint. Through further investigation, Sir James and Peter learn that the squire lived in Haiti for several years and practised Haitian voodoo rituals, as well as black magic. Meanwhile, Squire Hamilton, now with a vestige of Sylvia's blood, has begun using his voodoo magic to lure Sylvia into the dark woods. She is led to the abandoned tin mine by an army of walking zombies for a voodoo ceremony that will transform her into one of the walking dead. It is revealed that Squire Hamilton has been turning the locals into the walking dead, in order to create workers to mine the tin and make money off of it.

While Peter follows Sylvia to the mines, Sir James investigates the Squire's house and finds some small figures in coffins the Squire uses for his voodoo. After a struggle with one of the Squire's henchmen the room is accidentally set ablaze. Sir James barely manages to escape after threatening a servant, who notices the inferno, for information on the mine. He races to the mines to join Peter, while in the mansion the figures in the coffins catch fire, causing their zombie counterparts to do the same and go crazy. Using the distraction caused by the burning crazed zombies, Sir James and Peter rescue Sylvia and flee from the burning flames as they listen to the anguished screams of Hamilton and his zombies; thus the plague is ended.

Squire Hamilton's plot is uncovered, and the voodoo-driven zombie workforce is destroyed, ending the plague and freeing the village from the undead threat.

The climax sees the forces of rational investigation confront and defeat the supernatural evil manipulating the village for personal gain. With the squire's defeat, the unnatural hold over the dead is broken, restoring order and underscoring a theme of reason triumphing over dark superstition. The ending also resolves the tension between science and the occult that drives the film.