Dr. Bernard Adrian is a kindly scientist who seeks to cure a young woman's polio. He needs human spinal fluid to complete the formula for his experimental serum. Meanwhile, a vicious circus ape has broken out of its cage, and is terrorizing the townspeople. Can there be a connection?

• Monogram Pictures
• Boris Karloff
• Maris Wrixon
• Gene O'Donnell
• Dorothy Vaughan
• Henry Hall
• Selmer Jackson
• Gertrude Hoffmann
• Jessie Arnold