In this chapter, Holmes reveals the truth about the mysterious occurrences at Baskerville Hall to Watson and Sir Henry. He explains that the recent events were orchestrated by Stapleton in an attempt to get rid of Sir Henry so that he could inherit the Baskerville fortune.

Holmes tells the group that Stapleton is actually the descendant of the Baskerville line, not Sir Henry, as everyone had believed. He explains that Stapleton had been using the legend of the hound to create fear and drive Sir Charles to his death, and had also tried to use the same tactic on Sir Henry.

Holmes and Watson reveal that they had visited Stapleton’s home and discovered that he was keeping his wife captive, posing her as his sister to keep up appearances. They had also found evidence that Stapleton had been using a giant hound to carry out his plans.

The group decides to confront Stapleton, and they head out to the Grimpen Mire to find him. There, they come across Stapleton and his hound, and a struggle ensues. In the end, Stapleton falls into the mire and is killed by the quicksand.

The group returns to Baskerville Hall, where Holmes and Watson fill in the details of the case to Dr. Mortimer. The case is officially closed, and Sir Henry is able to take his place as the rightful heir of the Baskerville estate.

In the final scene, Holmes reflects on the case and the satisfaction of having solved it. He remarks that it is a reminder of the power of the human mind and the importance of using one’s intellect to solve problems.