Dr. Bernard Adrian is a kindly mad scientist who seeks to cure a young woman’s polio. He needs spinal fluid from a human to complete the formula for his experimental serum. Meanwhile, a vicious circus ape has broken out of its cage, and is terrorizing towns people.
Drama | Horror | Sci-Fi
| Boris Karloff | … | Dr. Bernard Adrian | |
| Maris Wrixon | … | Miss Frances Clifford | |
| Gene O’Donnell | … | Danny Foster | |
| Dorothy Vaughan | … | Mother Clifford | |
| Gertrude Hoffman | … | Jane, Adrian’s Housekeeper (as Gertrude W. Hoffman) | |
| Henry Hall | … | Sheriff Jeff Halliday | |
| Selmer Jackson | … | Dr. McNulty |