Briefly explain what happens in Chapter 14 in The Hound Of The Baskervilles, and why it is important to the novel as a whole?
The chapter opens with Holmes, Watson, and Lestrade preparing to execute Holmes' plot to expose the villainous Stapleton. As Holmes tends to be a secretive personality, the others are not sure about what exactly he has in mind, which adds to the suspense. The three arrive outside Merripit House, where they can see Sir Henry conversing with Stapleton. At one point, they hear Stapleton come out to the outhouse and unlock it, for a reason which is unclear.
Holmes is worried because a fog is rolling in, and if Henry does not start on his walk home soon, his plot will be foiled. Fortunately, Henry finally exits the house and starts across the moor, whereupon he is pursued by "an enormous, coal-black hound" with fire bursting from its mouth. Just as it overtakes the hapless Sir Henry, Holmes and Watson empty their revolvers into the hound, and it is killed.
Holmes notes that the dog's mouth is coated with phosphorus, which makes it appear to spew forth flames. In searching for Stapleton, the rescuers instead come upon his sister, who is in reality his wife. She has been tied and held captive in a room at Merripit House, and Stapleton is nowhere to be found. It is believed he perished in quicksand on the moor.
This chapter is important because it reveals the secrets behind the mysterious happenings on the Baskerville estate, and ties up the loose ends of the story. The villain Stapleton is exposed and his machinations explained, the legend of the hound is clarified, and even the fate of Mortimer's little spaniel is brought to light (Chapter 14).