•Why it earns a slot
The novel is the most celebrated Sherlock Holmes case, introducing the Dartmoor setting and the phosphorus-painted hound device that fuse rational detection with Gothic atmosphere in a way no other Holmes story matches.
When the heir to the Baskerville estate arrives in England under the shadow of a family curse involving a spectral hound, Sherlock Holmes sends Dr. Watson to Dartmoor to investigate while secretly following himself. The villain turns out to be a Baskerville descendant named Stapleton who has trained a real, phosphorus-daubed hound to terrorize and kill the family's heirs so he can inherit the fortune. Holmes springs a trap using Sir Henry as bait, the hound is shot dead, and Stapleton flees into the Grimpen Mire and is never seen again.
This distillation is written from the freely available original, which is always the better read when you have the time: gutenberg.org.