The Plague of the Zombies

Squire Hamilton uses Haitian voodoo to resurrect the dead as zombies so they can work in his abandoned tin mines. Since the mines are unsafe and no living workers will labor there, Hamilton exploits necromancy to create a free workforce for profit from the ore. This is the true source of the mysterious plague, he's been killing villagers and raising them as undead laborers.

Earlier in the film, Tom Martinus claims he saw his brother John walking near the mine, hinting that the dead were being used before the full revelation.

The plague was not a natural illness but a cover for Hamilton's necromantic activities. He was using voodoo to kill villagers and resurrect them as zombies for his mining operation. The 'plague' symptoms were actually the result of his victims being murdered and raised from the dead, with the fear and confusion spreading through the community as deaths mounted.

When Sir James and Peter disinter the coffins, they find them empty, suggesting someone is removing bodies from graves.

Hamilton uses Haitian voodoo practices involving blood sacrifice and small voodoo figures hidden in coffins. He collects blood from his victims, in Sylvia's case, he cuts her finger with shattered glass and secretly pockets a vial of her blood. This blood serves as a lure to draw his intended victim into the woods toward the mine where the transformation ritual takes place.

Sir James discovers small figures in coffins during his search of Hamilton's mansion, revealing the ritual implements.

The coffins are empty because Squire Hamilton has been digging up the recently buried bodies and taking them to the abandoned tin mine. There, he uses voodoo rituals to resurrect the corpses as zombies that will work in his mines. This is why the villagers initially suspect grave robbery rather than supernatural activity.

The funeral procession reveals John Martin's corpse when the casket falls, first exposing that something is wrong with the dead.

Hamilton needs Sylvia's blood as part of the ritual to transform her into a zombie. By obtaining her blood covertly, he can use it in a voodoo ceremony that will lure her to the abandoned tin mine and then raise her as one of the undead workers. Her blood is the key component for the final transformation ritual.

Hamilton shatters the wine glass specifically to cause Sylvia to cut her finger, revealing his deliberate plan to obtain her blood.

Alice Mary Tompson was murdered by Hamilton's zombie workforce and used as one of his undead miners. Sylvia discovers her grey-skinned body being hurled from the mine entrance by one of the reanimated dead. The autopsy reveals she shows no signs of rigor mortis and has a bandaged slash wound on her wrist, marks consistent with being killed and raised through voodoo.

Sylvia encounters the grey-skinned man near the mine headframe and witnesses him discarding Alice's body.

Hamilton targets Sylvia because he needs fresh victims to maintain his zombie workforce, and she is an outsider who won't be immediately missed. Her father's presence as a doctor actually makes her more useful, he can use the chaos of the 'plague' to cover his activities. Additionally, her blood type or physical condition may make her particularly suitable for the voodoo transformation ritual he plans.

Sylvia's interference with the fox hunters draws attention to herself, and Hamilton uses the opportunity to approach her.

Sir James sets fire to Hamilton's mansion while searching for evidence, creating a chaotic distraction. During the confusion, the fire spreads to the zombies gathered at the tin mine for the ritual. Peter follows Sylvia into the woods, and when the fire engulfs the area, the ritual is disrupted. James and Peter use the chaos to rescue Sylvia and flee while Hamilton and his undead army are consumed by the flames.

James finds the voodoo figures and struggles with a henchman, igniting the fire that becomes their escape opportunity.

Squire Hamilton perishes in the fire that engulfs his mansion and spreads to the mine area during the chaotic confrontation. His entire zombie workforce is destroyed in the flames as well. With Hamilton's death, the source of the necromancy is eliminated, and the mysterious plague ends because no more villagers will be killed and resurrected.

The fire ignites during James's confrontation with Hamilton's servants, creating the inferno that ultimately destroys the villain.

The animal blood on Alice's face was likely placed by Hamilton to mislead investigators. When the autopsy reveals the blood is of animal origin rather than human, it initially suggests Alice was killed by an animal rather than murdered by a person. This is part of Hamilton's cover-up to keep the true nature of his crimes hidden and direct suspicion away from himself.

This detail appears during the autopsy investigation, adding to the mystery that confuses the police.

The bandaged slash wound on Alice's wrist is a crucial clue indicating she was killed via ritualistic slashing, typical of voodoo sacrifices. This wound matches the method Hamilton uses to obtain blood from his victims before transforming them into zombies. The wound suggests she was deliberately cut to drain her blood for use in the necromancy rituals, a key part of his process.

This wound is discovered during the autopsy and serves as the first concrete evidence linking the deaths to ritualistic practices.

Hamilton's time living in Haiti and practicing Haitian voodoo is what gives him the knowledge to perform necromancy. This background reveals how an English squire possesses supernatural abilities to raise the dead. The revelation transforms the investigation from a murder mystery into a battle against dark magic, explaining how the impossible events are occurring.

Sir James and Peter discover Hamilton's Haitian past through investigation after Sylvia's fainting episode at Alice's funeral.

Hamilton uses zombies in the tin mines because the mines are notoriously unsafe and no living workers will labor there. By raising the dead, he creates a workforce that cannot refuse, complain, or die from the dangerous conditions. This allows him to profit from the ore without the expense or risk of employing living miners, making the operation highly profitable despite its moral horror.

The abandoned tin mine headframe appears early in the film, establishing the location that becomes central to Hamilton's scheme.