Dr. Buchanan (John Hurt) gets caught in a time slip that transports him back to Geneva at the time when Mary Shelley (Bridget Fonda) is writing her famous book "Frankenstein". As a sort of twist, the story isn't just fiction; Dr. Frankenstein (Raul Julia) and his Monster exist at the same time as Mary Shelley, and Dr. Buchanan interacts with all three of them.
The Monster demands a bride but Dr. Frankenstein refuses. The Monster then kills Dr. Frankenstein's fiance and as a result, Dr. Frankenstein brings her back to life ala his Monster.
Dr. Frankenstein aims a gun at the Monster and just before he fires it, the "Bride" grabs the barrel and points it at her chest so she is mercifully killed instead. In a fit of rage, the Monster attacks Dr. Frankenstein and kills him.. Dr. Buchanan then transports himself and the Monster to the future which is a frozen wasteland via another time warp where they fight and the Monster is killed.