In attempting to develop a chemical which would make a person super-intelligent, Dr. Montrose fails and the subjects of his experiments metamorphose into hideous monsters who band together and prey on humans. With the police stymied, a young detective attempts to track down the leader of the group of killers, known only to have a small crimson stain in one eye.
John A. Milton
Layton Parrish (as John Milton)Maurice Costello
Harold StanleyWilliam Cavanaugh
Doctor's AssistantEugene Strong
Robert ClaytonN.J. Thompson
Jim TannerOlga Olonova
Vanya ToscaEthel Grandin
Florence MontroseLorna Volare
Little girl