Mr. Bruff and Franklin meet back at Franklin's house and discuss further ways of investigating the diamond theft. Mr. Bruff suggests that they set a guard outside Mr. Luker's bank toward the end of the month and see who redeems the diamond. Franklin cannot wait that long and sets off at once to try to get Sergeant Cuff out of retirement. Arriving at Cuff's house, Franklin finds that he is visiting Ireland. Franklin leaves a card for him and returns to London.
Franklin next visits Mr. Bruff and announces his resolve to question all guests at the birthday dinner, beginning with the guests currently living in London. Mr. Bruff informs him that Miss Clack has moved to France, that Mr. Murthwaite is on his way to another Eastern adventure, but that Godfrey may be in London. A man at Godfrey's club gives Franklin several pieces of information about Godfrey: since his broken engagement to Rachel, Godfrey had become engaged to another heiress. This engagement had also been broken off due to a dispute over "settlements." Godfrey had then inherited 5,000 pounds from a rich, old, charity lady upon her death, and had used the money to travel to Europe.
Franklin next resolves to return to Frizinghall and question Betteredge about the other guests. Arriving at his hotel in Frizinghall, Franklin remembers hearing that Mr. Candy, who lives around the corner, wanted to speak to him and was also a guest at the birthday dinner.
Franklin goes to Mr. Candy's and finds the doctor much changed. Mr. Candy is a "wreck," dressed gaudily and unable to complete any thoughts. Candy seems to have something important to tell Franklin regarding the night of the birthday dinner, but he is unable to remember. Franklin gives up. On his way out, Ezra Jennings approaches him.
Ezra Jennings and Franklin begin to walk outside together. Franklin is intrigued by Jennings's strange appearance and feels sorry for him. Franklin is impressed that Jennings carries himself like a gentleman. Jennings explains that he was born of mixed parentage and raised outside of England in a colony.
Jennings broaches the subject of Mr. Candy's illness. He explains that Candy fell ill riding home in the rain from Rachel's party. Contrary to other doctors' orders to put him on depressants, Jennings put him on a steady diet of stimulants—champagne and brandy—until his pulse steadied. Jennings explains how he cried with "hysterical relief" when Candy began to improve—Jennings has a "female constitution." When Candy came to, he couldn't think or speak in complete thoughts. Jennings began to write down his mumblings in shorthand, filling in the gaps later to make sense of them.