Dr. Frankenstein and his monster both turn out to be alive, not killed as previously believed. Dr. Frankenstein wants to get out of the evil experiment business, but when a mad scientist, Dr. Pretorius, kidnaps his wife, Dr. Frankenstein agrees to help him create a new creature.
After experimenting on himself and becoming invisible, scientist Jack Griffin, now aggressive due to the drug's effects, seeks a way to reverse the experiment at any cost.
An ancient Egyptian priest named Imhotep is revived when an archaeological expedition finds his mummy and one of the archaeologists accidentally reads an ancient life-giving spell. Imhotep escapes from the field site and searches for the reincarnation of the soul of his lover.
