On his uncle’s death Sir Henry Baskerville returns from abroad and opens up the ancestral hall on the desolate moors of Devonshire. Holmes uncovers a plot to have Sir Henry murdered by a terrible trained hound. First casting of Rathbone and Bruce as Holmes and Watson.
A scientist working on cures for rare afflictions, such as a bone softening agent made from molds to allow him to correct the spinal deformity of his nurse, finds the physical causes of lycanthropy in wolf-man Larry Talbot and of vampirism in Count Dracula, but himself becomes afflicted with homicidal madness while exchanging blood with Dracula.
Graverobbers open the grave of the Wolfman and awake him. He doesn’t like the idea of being immortal and killing people when the moon is full, so he tries to find Dr. Frankenstein, in the hopes that the Dr. can cure him, but Frankenstein is dead and only his Monster is alive and this one wants to live, not to die like the Wolfman.