Sherlock Holmes and Dr Watson investigate the legend of a supernatural hound, a beast that may be stalking a young heir on the fog-shrouded moorland that makes up his estate. On his uncle's death Sir Henry Baskerville returns from Canada to take charge of his ancestral hall on the desolate moors of Devonshire, and finds that Sherlock Holmes is there to investigate the local belief that his uncle was killed by a monster hound that has roamed the moors since 1650, and is likely to strike again at Sir Henry.