Sherlock Holmes - The Hound of the Baskervilles, Part II

As Watson and Sir Henry investigate, they encounter the Stapletons, whose suspicious behavior adds to the mystery. Strange happenings and eerie signals heighten Watson's suspicions. Meanwhile, Holmes, working undercover, is close to unraveling the truth.
Holmes exposes Stapleton as the culprit and reveals Beryl's tragic situation as his coerced wife. The situation escalates when the hound attacks a man, believed to be Sir Henry. Holmes devises a plan to capture Stapleton using Sir Henry as bait.
With Inspector Lestrade's help, Holmes and Watson foil Stapleton's scheme. They rescue Beryl and witness Stapleton's apparent demise in the mire. Back in London, Holmes unveils Stapleton's true identity and reflects on their encounter with a formidable adversary.

Story from Arthur Conan Doyle, 1901–1902