Summary
After hearing Thaddeus's tale, the trio leaves Thaddeus's home in the coach, journeying to Pondicherry Lodge. Thaddeus accompanies them and leads the way. The porter at the lodge, McMurdo, is surprised to see them and refuses to allow Thaddeus's friends inside, since Bartholomew wasn't expecting them. Thaddeus, though, is free to enter.
Holmes quickly solves this problem: he recognizes the porter as a prizefighter whom he fought a while back; the two reminisce and the porter allows them in. Thaddeus is immediately worried since he doesn't see a light in Bartholomew's window, and he distinctly remembers telling his brother that he would be dropping by today.
They hear the whimpering of the housekeeper, Mrs. Bernstone, who is frightened, and Watson and Mary instinctively hold hands. The group is bewildered; Mrs. Bernstone tells them that she's been trying to talk with Bartholomew all day, but he requested that he be left alone in his study.
Holmes and Watson race upstairs to find Bartholomew dead, with a piece of paper by his hand that has the words 'the sign of the four' on it. Holmes finds something that looks like a thorn stuck in Bartholomew's neck, and says that it is poisoned.
Watson removes and examines it. Thaddeus exclaims that the treasure is gone; at Sherlock's urging, he goes down to the police station to report both the murder and the theft. Sherlock finds the muddy imprint of a wooden leg outside the window of Bartholomew's room and declares that the case is simple, to Watson's astonishment.
Sherlock then clarifies that the wooden-legged man must have come through the roof, showing Watson a hidden trapdoor that leads out onto the roof. Watson concludes that Bartholomew was poisoned by something like strychnine, just as the police are pounding up the stairs.
The police officer Athelney Jones makes his appearance in the room and speculates with Holmes about what happened, but all of his theories have obvious flaws. Jones arrests Thaddeus on the charge of his brother's murder, but Holmes assures Thaddeus that he will get him out in no time. Jones does not seem to like Holmes very much at all.
Holmes asks Watson to fetch a dog named Toby for him, who has a great nose, and to bring Mary home.
Analysis
Throughout these chapters, Watson is constantly bemused and astonished by Holmes's powers of deduction. Watson incorrectly assumes that because the footprint is small, the murderer must be a child. Sherlock is amused by this idea and suggests that it is not the case, showcasing his ability to look at the details and see the bigger picture, rather than merely the disparate pieces.
In "The Tragedy of Pondicherry Lodge," we see Watson and Mary grow even closer, though they have just met that day. They hold hands and find comfort in one another even though they are virtual strangers.
We also see some of Holmes's humor in the way he greats the police: "Hallo! Here are the accredited representatives of the law" (112). He is wry and sarcastic with his wit, something that we have only glimpsed a little bit so far in the story.
The reader also realizes that though Holmes may be the only person who can piece the puzzle together, he has a lot of help. Certainly, the police officer Jones only serves to get in the way, but Holmes asks Watson to bring the dog Toby, implying that he relies on others for their help as well. Though Holmes is a larger-than-life personality, he doesn't work miracles of deduction without help from his friends.
