A humane scientist attempts to explore the most loathsome forces of evil behind the doors of his London laboratory.
Dr. Jekyll has lived a life of high-minded respectability and scientific aspiration among friends for many years, so when, gradually and inexplicably, he begins to withdraw from society and presents his lawyer with a bizarre new will, his associates are baffled and suspect blackmail. The key to the mystery appears to lie with the sinister Mr. Hyde, who has begun to stalk the foggy streets of London, producing an inexpressible terror in those he encounters, and exerting a powerful control over the helpless Dr. Jekyll.
