Unusually for a story involving the great detective Sherlock Holmes, The Hound of the Baskervilles is a full length novel and the longest Holmes adventure - the most famous story of the most famous detective in the world. Taking place in both London and Devon, the novel traces the story of American Sir Henry Baskerville, the heir to a considerable estate after the death of Sir Charles Baskerville of a heart attack. Due to a West Country legend about a huge demon dog roaming the moors and seeking an ancient vengeance against the Baskervilles, locals are convinced that Sir Charles' death was no accident. Sherlock Holmes is invited by a certain Dr. Mortimer to investigate the matter for the benefit of Sir Henry. Holmes and his sidekick Watson who is sent ahead to Devon are drawn into a fatal adventure of superstition and revenge on the barren, gloomy moors in this hugely enjoyable mystery.