The discovery of a perfectly preserved caveman prompts a mad scientist to attempt a daring brain transplant.

University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.

Baron Victor Frankenstein has discovered life's secret and unleashed a blood-curdling chain of events resulting from his creation: a cursed creature with a horrid face — and a tendency to kill.

Rescued from the guillotine by his devoted dwarf Fritz, the Baron relocates to Carlsbruck, where he continues his gruesome experiments.

Frankenstein's unscrupulous colleague, Dr. Bohmer, plans to transplant Ygor's brain so he can rule the world using the monster's body, but the plan goes sour when he turns malevolent and goes on a rampage.

Blackmailing a young couple to assist with his horrific experiments the Baron, desperate for vital medical data, abducts a man from an insane asylum. On route the abductee dies and the Baron and his assistant transplant his brain into a corpse. The creature is tormented by a trapped soul in an alien shell and, after a visit to his wife who violently rejects his monstrous form, the creature wreaks his revenge on the perpetrator of his misery: Baron Frankenstein.

Dr Simon Helder, sentenced to an insane asylum for crimes against humanity, recognises its director as the brilliant Baron Frankenstein, the man whose work he had been trying to emulate before his imprisonment. Frankenstein utilises Helder's medical knowledge for a project he has been working on for some time. He is assembling a man from vital organs extracted from various inmates in the asylum. And the Baron will resort to murder to acquire the perfect specimens for his most ambitious project ever.

A scientist's reckless experiment turns a man into a half-ape creature, whose monkey-like antics bring confusion and alarm to his surroundings. After a series of comic disruptions, the effects of the transformation are reversed, underscoring the folly of tampering with nature.

Once again Paula the ape woman is brought back to life, this time by a mad doctor and his disfigured assistant, who also kidnaps a nurse in order to have a female blood donor.

A white man's brain is transplanted into a black man's skull.

After a traffic accident Kaylie is in coma for months and her doctors want to try a new procedure on her. To regain her consciousness, they stimulate her brain with the neural patterns of a woman who has just died. It works and Kaylie fully recovers. However, she begins to relive the dying moments of her donor and realizes that she was murdered! Along with her husband and mother, she tries to find out what happened.

Amir, the benevolent ruler of Kalid, is dying, but there is hope. Freshly deceased, he is flown to the United States where Dr. Trenton transplants his brain into the body of a simpleton in a classic "assistant got the wrong kind of body" plot line. Dr. Trenton has a few nefarious plot twists of his own in mind, and then there's the thing with the dwarf and the women chained in the basement. It's up to Amir's friend Bob and wife Tracey to try and salvage this tale.