Dr. Henry Jekyll (John Barrymore) is working on separating the good and evil aspects from a person's persona and comes up with a potion that holds the key. Using himself as a guinea pig, Dr. Jekyll drinks his formula and is transformed into the evil Mr. Hyde. Mr. Hyde's activities are the scandal of the city and are a major, though secret, embarrassment to the kindly Dr. Jekyll. Dr. Jekyll attempts to keep his connection to Mr. Hyde a secret, all the while he cannot put aside that aspect of his personality which he has released.