The theme of intoxication or drugged states recurs strongly in these chapters and is used to describe the state of the Verinder household after the crime has been committed. Betteredge admits to having caught "detective fever," under which influence his actions and interests are not his own. Further on, he explains, "The horrid mystery hanging over us in this house gets into my head like liquor, and makes me wild." Thus, drugged states of mind are connected with both the mystery of the exotic Moonstone and with the obsessive behavior necessary to detect the thief. The theme is eventually related, also, to the particularly desperate lovesickness of Rosanna Spearman. When Betteredge confronts Rosanna about her suspicious behavior toward Franklin Blake and tries to comfort her about Franklin's rejection of her, Rosanna is continually described as acting "like a woman in a dream." Just as drugged or intoxicated individuals have little power over their thoughts or actions, Rosanna is described as being "like a creature moved by machinery."

It is in part because of this helpless behavior that Rosanna is consistently treated as an object of pity by everyone, including Sergeant Cuff. Though Rosanna clearly has something to hide in the wake of the crime, no one except Franklin Blake, who is in search of a scapegoat to clear Rachel from suspicion, believes that she could have committed the crime without orders from another.

The surveillance aspect of the detection process emerges strongly in these chapters. Cuff practices his own surveillance campaign—he eavesdrops on Franklin and Rosanna's conversation, he follows Rosanna's footprints on the Shivering Sand, and he hides overnight in the hallway in hopes of spying on a clandestine meeting between Rosanna and Rachel. Yet other characters practice surveillance as well, such as Penelope's spying on Rosanna's love of Franklin. A big country house such as the Verinder house provides ample opportunity for this type of observation and features of the house seem to figure into the atmosphere of surveillance. We see Betteredge and Cuff standing outside looking at Rachel's upstairs window, and short hallways nearly hide the identity of eavesdroppers.

In these chapters, Rosanna remains the main object of investigation, though she is not primarily under suspicion. Cuff and Betteredge track her movements, which lead them outside the walls of the Verinder house. Rosanna visits both Frizinghall and Cobb's Hole, thus the setting of the novel shifts from the Verinder house for the first time with Cuff and Betteredge's visit to Cobb's Hole. Though the movements of characters include Frizinghall, the town itself will not be shown at all in this narrative, as Betteredge, the narrator, must remain close to the house in his capacity as steward.