Watson is pissed at having been fooled by his friend. Holmes tells Watson that Jack and Beryl are really married, not brother and sister, and that Jack has been stringing Laura along on the side. They guess that Jack was the spy back in London and that Beryl sent Henry the note warning him not to return to the Baskerville mansion.
Suddenly, they hear someone screaming nearby, and then the freakish, haunting groan of the dog from Hell. They run toward the noise and find the body of the escaped killer, who fell from a cliff while running. They meet Jack, suspiciously wandering through the dark. He seems disappointed the corpse is not Henry.