The Hound of the Baskervilles is said to be the best book in the Sherlock Holmes canon as rated by Sherlockians from all over the world in 1999. Completing only three stories thus far, I’d rate this one high above the earlier stories, too.
As the title suggests, the story is about a menacing hell-hound stalking the Baskerville family. It’s a curse that has dogged them for generations and has caused concern about the manor one day being unoccupied. Not long into the story, the supernatural hound claims another Baskerville, which prompts a visit to 221B Baker Street.