The Hound of the Baskervilles

Dr. Richard Mortimer recounts to Sherlock Holmes and Doctor Watson in Baker Street the legend of the Hell hound that killed the devilish Sir Hugo Baskerville in retaliation for his misdeeds, including murdering the daughter of a servant. He asks Holmes to investigate the death of his friend Sir Charles Baskerville, in Dartmoor, from heart failure, in the moor surrounding his estate, Baskerville Hall, with a look of horror on his face. Mortimer fears for the life of Sir Henry, Sir Charles' nephew and heir, who's just come from South Africa to take possession of his inheritance and of Baskerville Hall.
Although sceptical, Holmes and Watson agree to meet Sir Henry who complains that one of his boots is missing. Mortimer tells them that the Baskerville estate is worth about £1,000,000. A peculiar threat from a dangerous tarantula convinces Holmes that Sir Henry's life is in danger. Claiming that he cannot come to Baskerville Hall himself, Holmes dispatches Watson to Dartmoor with Mortimer and Sir Henry. Holmes tells Sir Henry not to go out onto the moor after dark.
On their way to Baskerville Hall, the trio learns that Selden, a convicted murderer, has escaped Dartmoor Prison and is hiding on the moor. At Baskerville Hall, Mr. Barrymore, the butler, and Mrs. Barrymore, the housekeeper show them around the mansion. One of two portraits of Sir Hugo is missing, and the Barrymores say it was mysteriously stolen months before. The next day, Sir Henry and Watson meet Bishop Frankland, a bishop and keen entomologist. Watson gets trapped in a patch of mire in the Grimpen Mire and is saved by a farmer named Stapleton and his daughter Cecile, a girl who bewitches Sir Henry.
That night, Watson and Sir Henry investigate a light on the moor. They briefly encounter a strange man who flees in the shadows, and a distant hound howls, provoking in Sir Henry a mild heart attack. Watson spots a man on a hill in the distance while helping Sir Henry back to Baskerville Hall. Watson discovers it to be Holmes, who has concealed his own arrival to investigate more freely.
Selden, wearing Sir Henry's clothes, is slaughtered by the unseen hound. Holmes and Watson find his body mutilated in a ritual, and the legendary curved dagger of Sir Hugo. The Barrymores confess to have helped Selden, who was their relative, by supplying food and clothes each time he signaled with a light from his hideout. Holmes is convinced that neither the Barrymores nor Selden are connected to the death of Sir Charles. He also figures that the tarantula found in London was stolen from Bishop Frankland.
After surviving personal danger in an abandoned tin mine while looking for evidence of a hound, Holmes is able to deduce who unleashed the hound in pursuit of Sir Charles. Holmes explains about questioning Barrymore about the missing portrait; it was stolen because it revealed the fingers on Sir Hugo's right hand were webbed just like Stapleton's. Finding the dagger stolen, Holmes and Watson follow Sir Henry and Cecile to the moor. Cecile takes Sir Henry to the ruins where Holmes and Watson hear Cecile reveal her intentions to a horrified Sir Henry, revealing that she and her father are also descendants of Sir Hugo, planning to claim the inheritance as their own once Sir Henry is dead. The hound appears and attacks Sir Henry, until Holmes shoots it, causing it to back off. With Sir Hugo's curved dagger, Stapleton attempts to attack Watson, who shoots and wounds him. The wounded hound attacks Stapleton and fatally mauls him. Holmes shoots and kills the hound. Sir Henry is unscathed from the mauling as Holmes reveals the hound to be an ordinary dog wearing a mask to make it look more terrifying. Cecile tries to flee across the moor, only to fall into the Grimpen Mire and sink to her death as Holmes and Watson take a shocked Sir Henry back to Baskerville Hall. Back in Baker Street, Holmes and Watson are given by Sir Henry the stolen portrait of Sir Hugo that was found on the Stapleton farm.