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.

A dangerous combination of radiation and insecticide causes the unfortunate Scott Carey to shrink, slowly but surely, until he is only a few inches tall. His home becomes a wilderness where he must survive everything from spiders living in the cellar to his beloved cat.

Wrongfully convicted of a robbery and murder, Paul Lavond breaks out of prison with a genius scientist who has devised a way to shrink humans. When the scientist dies during the escape, Lavond heads for his lab, using the shrinking technology to get even with those who framed him and vindicate himself in both the public eye and the eyes of his daughter, Lorraine. When an accident leaves a crazed assistant dead, however, Lavond must again make an escape.

A dark and stormy night in a drugstore. The druggist mixes a potion and falls asleep. The skull-and-crossbones on the bottle comes to life and drips the potion on the druggist.