Dr. Morgan and Dr. Cavigny star as a brace of scientists who return from the West Indies with a potent, phosphorescent serum that allegedly changes human beings into cats.

An atomic explosion awakens Gammera, a giant fire breathing turtle monster from his millions of years of hibernation.

Jenny Marsh, recently released from prison for killing a man, finds herself under the watchful eye of her parole officer, Griff Marat, who helps her secure a job caring for his ailing mother.