Larry Talbot finds himself in an asylum, recovering from an operation performed by the kindly Dr. Mannering. Inspector Owen finds him there, too, wanting to question him about a recent spate of murders. Talbot escapes and finds Maleva, the old gypsy woman who knows his secret: when the moon is full, he changes to a werewolf. She travels with him to locate the one man who can help him to die - Dr. Frankenstein. The brilliant doctor proves to be dead himself, but they do find Frankenstein's daughter. Talbot begs her for her father's papers containing the secrets of life and death. She doesn't have them, so he goes to the ruins of the Frankenstein castle to find them himself. There he finds the Monster, whom he chips out of a block of ice. Dr. Mannering catches up with him only to become tempted to monomania while using Frankenstein's old equipment. Larry Talbot chips Frankenstein's monster out of a block of ice. When Talbot changes to the Wolf Man, the two creatures do battle.
