Sherlock Holmes - The Hound of the Baskervilles

In London, Dr. James Mortimer seeks Sherlock Holmes's assistance regarding the infamous Baskerville family curse. The legend dates back to the English Civil War when Sir Hugo Baskerville's encounter with a demonic hound led to tragedy. Mortimer recounts the recent death of Sir Charles Baskerville, supposedly caused by the curse. Sir Henry Baskerville, Sir Charles's nephew and heir, becomes the new target of Mortimer's concern.
Despite dismissing the curse as superstition, Holmes agrees to meet Sir Henry, who is arriving from Canada to claim his inheritance. Mortimer shares his fears about potential harm to Sir Henry, especially considering his substantial inheritance. Holmes, recognizing the danger, asks Watson to accompany Sir Henry and Mortimer to protect the baronet and investigate the mysterious events.
The trio arrives at Baskerville Hall, where they encounter the Barrymores, the estate's butler, and housekeeper. The proximity of the estate to Grimpen Mire, a treacherous marshland, adds to the ominous atmosphere. Meanwhile, an escaped convict named Selden lurks on the moor, further complicating matters. The eerie surroundings and peculiar residents contribute to the growing sense of unease.
As Watson and Sir Henry explore the neighborhood, they encounter the Stapletons, a brother and sister duo, whose behavior raises suspicions. Strange occurrences, including distant howls and mysterious signaling, intensify Watson's apprehension. Amidst the investigation, Watson discovers Holmes secretly present on the moor, close to solving the mystery.
Holmes reveals Stapleton as the prime suspect and uncovers the shocking truth about Beryl, who is Stapleton's abused wife, forced to pose as his sister. The situation escalates when the hound kills a man on the moor, believed to be Sir Henry. Holmes devises a plan to catch Stapleton, using Sir Henry as bait.
With Inspector Lestrade's assistance, Holmes and Watson successfully thwart Stapleton's plan. They discover Beryl tied up in Stapleton's house, and Stapleton himself seemingly drowns in the mire during his escape attempt. Back in London, Holmes reveals Stapleton's true identity as Sir Henry's cousin, Rodger Baskerville, and reflects on their encounter with one of their most formidable foes.
Story from Arthur Conan Doyle, 1901-1902