Cuff and Betteredge take a walk in the garden, and Cuff notices Rosanna lurking in the shrubbery. Betteredge explains Rosanna's love for Franklin and that Franklin often walks in that garden. Cuff accepts this explanation.
Cuff asks Betteredge if anything amiss passed in the servant's hall the night of the theft. Betteredge instinctively protects his fellow servants and says, "no." Cuff senses Betteredge's stubbornness and makes Betteredge feel guilty by telling him that he (Cuff) likes him.
Cuff interviews each of the servants individually—some come out indignant and angry and others proud and happy. After the interviews, Cuff tells Betteredge to let "poor" Rosanna leave the house if she asks to, but to tell him first. Betteredge questions the angry servants and learns that they had reported to Cuff that Rosanna was burning her fire at four in the morning the night after the theft and that Cuff acted as through he didn't believe them. Betteredge realizes that Cuff has cleverly kept the women from putting Rosanna on her guard by pretending to disbelieve them.
In the garden, Betteredge tells Franklin of the servants' report of Rosanna's suspicious behavior. Franklin determines to report Rosanna's guilt to Lady Verinder, but Cuff walks up and stops him from doing so, reminding him that Rachel's guilt is also still at issue. Franklin is insulted at this implication of Rachel and walks away. Cuff asks Betteredge to show him to the Shivering Sand.
In these chapters, the character of Sergeant Cuff is introduced, representing another feature of The Moonstone that would set the standard for future detective novel staple characteristics. Future detective novels would feature the dynamic of the bungling local police (Superintendent Seegrave) replaced by a more intelligent detective (from a nearby metropolis—London in Cuff's case). The particular character of Cuff—his tall, thin figure, his soft- spoken personality, and his idiosyncrasies, such as his love for roses, and whistling "The Last Rose of Summer"—would also set a standard for future quiet, unexpectedly clever, idiosyncratic detectives, including Sherlock Holmes. Cuff is shown within Betteredge's narrative to be superior to Seegrave in detection intelligence but also in his ability to feel compassion. Unlike Seegrave, Cuff exhibits sympathy for Rachel's agitated state, the agitated state of the servants, and Rosanna's love for Franklin. Cuff is perceptive, not just of clues and crimes, but of other characters' positions and feelings. Finally, though he will guess the circumstances of the diamond theft incorrectly, he is still shown to be one of the prophets of the novel when he correctly foreshadows the peculiar non-criminal circumstances of the crime at the end of chapter XII: "Nobody has stolen the Diamond. Wait a little. The pieces of the puzzle are not all put together yet."
The Moonstone revolves around two main mysteries: the current location of the stolen diamond and how the initial crime took place, yet many other smaller mysteries exist within the plot as part of the larger investigation. In these chapters, the smaller mystery that dominates attention is the mystery of why Rachel mistreats everyone, especially Franklin Blake, and is so uncooperative with the investigation. When Cuff begins to suspect Rachel, and to let others in on his suspicion, it creates a division between the characters—specifically Lady Verinder, Franklin Blake, and Betteredge. What began as a united investigative front ends up fractured and distrustful. This internal division and Rachel's uncooperativeness ensure that the crime will not be solved in this early narrative.