A great many of the Sherlock Holmes stories turn out to be about money, even though the mercenary motif is not visible at the beginning. Some examples are "The Speckled Band," "The Solitary Cyclist," "The Blue Carbuncle," and "The Red-Headed League." "The Hound of the Baskervilles" appears to be a story about the supernatural, a subject in which Sir Arthur Conan Doyle was keenly interested. However, it turns out that one of Sir Henry Baskerville's neighbors, Mr. Stapleton, is exploiting an old legend about a gigantic mythical hound to kill off the two men who are ahead of him in line of succession to the Baskerville estate. Stapleton keeps a vicious hound in a secret place and has used it already to cause the death of Sir Charles Baskerville of an apparent heart attack. Stapleton occasionally allows the hound to run free at night in order to terrify everyone in the region and to perpetuate the legend that there is indeed a ghost-hound that haunts the moors. If Stapleton can succeed in having his hound kill Sir Henry, he will be able to claim the Baskerville estate. However, he cannot expect a young man like Sir Henry to die of a heart attack upon seeing the hound painted with phosphorous. The hound will have to kill this victim, and Stapleton would of course be guilty of premeditated murder.
As is characteristic of most Sherlock Holmes stories, the great detective explains many of the essential details to his friend and biographer at the end. In Chapter XV, "A Retrospection," Holmes tells Watson:
“My inquiries show beyond all question that the family portrait did not lie, and that this fellow [Stapleton] was indeed a Baskerville. He was a son of that Rodger Baskerville, the younger brother of Sir Charles, who fled with a sinister reputation to South America, where he was said to have died unmarried. He did, as a matter of fact, marry, and had one child, this fellow, whose real name is the same as his father."