Chapter XII: Death on the Moor
Watson is naturally astounded, and more than a little offended, to find Holmes there. Having been kept out of the loop, he believes his reports have been wasted, and that Holmes has used him as a pawn. However, Holmes insists that Watson's reports - which were stopped at Combe Tracey and brought to Holmes by Cartwright, whom accompanied Holmes from London - have proven extremely useful. Holmes deduces how Watson found him and then asks for what new information he learned in his visit to Laura Lyons.
After Watson shares his information, Holmes shares his own: there is record of a relationship between Stapleton and Laura, leading Holmes to believe Stapleton the culprit. Holmes has uncovered that Miss Stapleton is actually Stapleton's wife, not his sister. This is why Stapleton so vehemently opposed any union between her and Sir Henry. Through research, Holmes has learned that Stapleton was indeed a schoolmaster who lost his job, but that he had operated under a different name and then disappeared without a trace. Holmes has deduced that not only was Stapleton the bearded man in London, but that his wife must have been the person who tried to warn them. Clearly, Stapleton believes he can gain some benefit from lying about his wife's identity.
Right as Holmes admits that Stapleton's plan must be murder, the men hear the hound's cries out on the moor. They rush out towards the direction of the sound, Holmes lamenting that Stapleton has struck before Holmes could ensnare him. As they arrive near the source of the sound, they hear a human moan and then see a body fall from a great height. They recognize Sir Henry's clothes on the figure, and realize their charge is dead.
They both blame themselves - Watson for leaving Sir Henry alone, Holmes for having delayed his action - and then climb onto the rocks to try and spot the hound. Instead, they spot the Stapleton house and briefly plan how to ensnare the culprit. Suddenly, Holmes realizes that the corpse has a beard - it is not Sir Henry, but Selden! Watson realizes that Barrymore must have given Sir Henry's extra clothes to the man.
They then wonder two things: why Selden would have been so frightened of the sound, and why Stapleton would have thought to release the hound on this night.
Before they can answer either, Selden strolls up, surprised to see them. His surprise is even greater, though, to discover the convict's body. He claims he heard the sound as well, and then quickly identifies Holmes. The men talk vaguely as Holmes sizes him up, and then decide they must leave the body with something over its face until the next day.
Chapter XIII: Fixing the Nets
As they walk across the moor, Holmes explains to Watson that they lack sufficient evidence to secure Stapleton's arrest. They have neither determined a motive nor actually seen the hound. Holmes plans to tell Laura Lyons about Stapleton's marriage, in hopes that she will then work with them against him.
Before they arrive at Baskerville Hall, Holmes warns Watson not to say anything of the hound. Pleased to see Holmes has arrived, Sir Henry joins the men at dinner. Before they eat, Watson breaks the news of Selden to Barrymore and his wife, who are quite saddened.
As they dine, Sir Henry tells them that Stapleton had invited him to dinner that night, but that he did not want to break his promise to stay away from the moor at night.
Holmes then drily remarks that the convict had been wearing Sir Henry's clothes when he died. In response to Sir Henry's surprise, Holmes begins to lay out a plan, but his attention is struck by the line of portraits on the opposite wall. He observes that Hugo Baskerville looks quite meek in his portrait, and Sir Henry adds that the canvas is dated 1647.
After dinner, Holmes brings Watson to the portrait and leads the latter to recognize that the picture resembles Stapleton, if one ignores the hair and focuses solely on the facial shape. They have finally discovered the missing link of their mystery: Stapleton is a Baskerville!
The next morning, Holmes instructs Sir Henry to dine that night with the Stapletons, and to travel there alone. He further tells him that he and Watson intend to return to London, on urgent business. Though upset at being abandoned, Sir Henry agrees to follow Holmes's instructions.
Watson and Holmes head to the train station, to perpetuate the ruse. There, Holmes directs Cartwright to take the train and to send a telegram from London to Sir Henry Baskerville. Cartwright also delivers a telegram that had arrived for Holmes, from Inspector Lestrade, a London police officer. The message informs Holmes that Lestrade will arrive later that day with an unsigned warrant.
Watson and Holmes then visit Laura Lyons. Holmes is very straightforward with her: he accuses her of withholding information that pertains to Sir Charles's death, and informs her that he believes she is implicated alongside Stapleton and his wife for it. Though shocked, she is eventually convinced that the man is indeed married. She then cooperates, explaining that Stapleton had offered to marry her if she could get divorced, but then had convinced her to break her appointment with Sir Charles, promising he could obtain the money himself. Finally, he had frightened her into remaining silent, suggesting she would be found guilty for his death. Holmes tells her she is lucky to remain alive.
After they leave, Holmes declares that they will be able to construct a cohesive narrative of the mystery by the end of that night. They then fetch Lestrade from the train station and head into Dartmoor, where Baskerville Manor is located.
Holmes' investigation finally begins to yield results, as the metaphoric 'net' is transferred into his court. Significantly, we discover that his game of detection is a game of wits: Holmes must figure out how to trick Stapleton into believing he is really uninterested in the case. First, this approach parallels Stapleton's own. Both men lead others to assume things about them, rather than forcing those impressions on others.
Further, both men have certain personal habits in common. Consider the esoteric behavior attributed to Homes in the early chapters. His daily life and habits are quite disorderly, and he lacks a certain social intelligence. The meticulousness of his method is at great odds with his daily habits. This suggests Doyle's belief that a life purely of the mind has little room for the trappings of a 'normal' life.
Secondly, this game of wits is complicated by the necessity of proving his deductions before the law. Though in many ways a pawn in the plot, Lestrade is also a crucial component; if he does not witness the crime, then Holmes's brilliance can yield no dividends. His own interpretation cannot reach the level of truth until it can create conviction in two senses: readerly conviction and legal conviction. Holmes must endanger characters in the novel because his interpretation may not otherwise fulfill both of these requirements. When he laments the death of Sir Henry (who is actually Selden, of course) he is lamenting this shortcoming, the fact that he had to risk the man's life in order to secure both convictions of the culprit.
In other words, this necessity for legal status parallels Doyle's requirements to make this story an "interesting" case (192). It is notable that the detective story usually consists of a crime that is committed in the past, and investigated in the present. However, the investigation might sometime seems dull if it did not itself involve crime and action. Here then we have that crime coming alive. History is here repeating itself.
The conflict between Holmes and Watson reaches its apex in Chapter XII, when Watson accuses Holmes of using him. Later, Holmes calls Watson a man of "action," contrasting that with his own intellectual nature. In many ways, Holmes does use Watson as he uses anyone else. Knowing his friend's active nature, he had to keep Watson in the dark in order to best use that personality trait. That Holmes cannot empathize with Watson's sense of betrayal is just one of the sacrifices he makes to follow his own singular path. Action is important, but must always be subsumed to the intellect, which alone holds the power. For Doyle and Holmes, this is true both in ourselves and in the symbolic representation of Holmes and Watson.
Finally, it is notable that women are not presented in a very flattering way in this novel. Holmes never really had love interests, and the novel's only deep relationship is the friendship between Holmes and Watson. Here, despite her good intentions, Miss Stapleton is used mostly as a foil, to both the villain and Sir Henry. Laura Lyons, moreover, is motivated solely by finding the proper husband, and is easily manipulated by Stapleton and then by Holmes. Overall, women tend not to be as clever as men in Doyle's work, and they are often too fearful for their own lives to be of much help. Clearly, gender was not a primary theme in Doyle's mind, but his representation of women leaves much to be desired for a modern reader.