In London, Dr. Richard Mortimer asks Sherlock Holmes and Doctor Watson to investigate the death of his friend Sir Charles Baskerville, in Dartmoor, found dead by heart failure, lying in the moor surrounding his estate, Baskerville Hall. Mortimer believes that his good friend had been scared to death by the vision of a ghost hound, the same that centuries before killed Sir Charles's ancestor, the devilish Sir Hugo, and relates the story of the "curse of the Baskervilles", portrayed a flashback scene. Mortimer tells Holmes that he also fears for the life of Sir Henry Baskerville, Sir Charles's heir, who's just come from South Africa to take possession of his inheritance and of Baskerville Hall.