Baron von Frankenstein, Udo Kier, neglects his duties toward his wife/sister Katrin, Monique van Vooren, as he nurses a chilling obsession: to forge a perfect Serbian race by grafting together parts from corpses to create a male and a female progeny. His methodical fixation merges medical precision with a domineering hunger, and he even uses the surgical wounds of his female creation as a conduit for his own lust. Frustrated by the insufficient reproductive drive of the male creature, he searches for a head donor with a stronger libido, and he studies the creature’s nasum—the nose—believing its shape to be a telltale mark of true Serbian lineage.
A suitably ardent farmhand named Nicholas, Joe Dallesandro, leaves a local brothel with his repressed friend, and they are spotted by the doctor and his henchman Otto. The duo mistakes the prospective monk for a suitable stud and seizes Nicholas’s head for use on the male creature. Unaware of these backstage machinations, Nicholas survives the kidnapping and is summoned by Katrin to the castle, where a tense pact forms: he will gratify her carnal appetites.
During a formal dinner with the castle’s residents, the male and female creatures are presented under Frankenstein’s chilling control, while the male creature shows no sign of recognizing his friend as he serves the doctor and his kin. Nicholas begins to sense something is terribly wrong, yet he pretends not to notice as he probes for clues. A dispute with Katrin—driven by her own wants—sends Nicholas rummaging through the laboratory, where he is captured by the doctor. Frankenstein muses about swapping the male creature’s head for the donor’s, hoping to ignite a new, more vigorous libido. Katrin, rewarded for betraying Nicholas, is granted continued access to the creature, but her triumph ends violently during an intensely erotic, overpowering embrace that kills her.
Elsewhere, Otto repeats the doctor’s sexual escapades with the female creature, culminating in a graphic disembowelment. Frustrated and enraged, Frankenstein returns and dispatches Otto. He then plots to force the male creature to eliminate Nicholas, but the remnants of Nicholas’s friend’s personality fight back, and the doctor is slain in a grisly fashion. The male creature, convinced his life is no longer worth living, disembowels himself. As dawn breaks, Frankenstein’s children, Erik and Monica—Marco Liofredi and Nicoletta Elmi—enter the laboratory and wheel the crane that holds Nicholas in mid-air. The device lifts him higher into the air, and the two children brace themselves, scalpels gleaming, as they prepare to seal the predator’s fate.
