Coffin Joe returns to his village after a hospital recovery from shock and blindness, still driven by a singular obsession: to find the "perfect" woman to sire a son of superior blood. Accompanied by his gaunt, hunchbacked servant, he abducts six beautiful women on his first night back and subjects them to a brutal series of trials designed to test who among them displays no fear. Among the captured, Marcia remains calm and defiant while the others scream in terror. Coffin Joe marks her as his chosen one and confines the other five in a pit beneath his bedroom, releasing venomous snakes to kill them. When Marcia resists his sexual advances, he frees her, claiming she will not report him to authorities.
Shortly after, the colonel’s daughter, Laura, arrives in the village and quickly draws Coffin Joe’s attention. He invites her to meet at midnight, and she quickly falls in love with him. The colonel and his other son try to keep Laura away, but their efforts fail. In a bid to sever the threat, the colonel offers Coffin Joe a large sum of money to leave Laura alone. Coffin Joe and his loyal servant capture the colonel’s emissary, and brutally kill him, later framing the colonel’s thug Truncador for the murder.
Coffin Joe’s grim world further darkens when he learns that one of the kidnapped women he killed with snakes was pregnant. Overcome with guilt, he experiences a nightmare in which he is dragged through a graveyard into Hell, witnessing its denizens suffer endlessly. The Devil appears to be a reflection of himself, which only hardens his belief that his actions are not wrong.
Back in town, Truncador escapes from jail and reunites with the colonel, who wishes Coffin Joe dead for seducing his daughter. He dispatches Truncador to assemble a new team of killers, and that very night they ambush Coffin Joe, though he manages to kill them all. Meanwhile, Marcia, haunted by the victims’ deaths, drinks arsenic and confesses Coffin Joe’s crimes to the doctor and the gathering townspeople. A lynch mob forms under the colonel’s order and closes in on Coffin Joe.
In a race against fate, Laura is ready to give birth, but a doctor’s assessment makes it clear that only one life can be saved. Coffin Joe and Laura decide that the baby should live, but the operation ends in tragedy for both of them. Coffin Joe carries Laura’s body to a mausoleum in the cemetery, where the villagers close in. He attempts to flee but is shot and falls into the pond where he once dumped his victims. In the final moment, a priest pleads with him to accept God so his soul can be saved. Coffin Joe concedes, accepting God as his savior, and drowns in the pond as skeletal figures rise to the surface.
