Having had his breakfast at Chesney Wold, Mr. Bucket informs the butler Mercury that he is ready to have his conference with Sir Leicester Dedlock. By and by, Mr. Bucket goes to the library where he waits for Sir Leicester who is late on account of the gout which has flared up due to Mr. Tulkinghorn's death and the agitation that that has caused.
Presently, with Sir Leicester's permisssion, Mr. Bucket locks the door of the library and begins to inform Sir Leicester of his--Mr. Bucket's--investigations. He tells Sir Leicester that Mr. George isn't the murderer, that Mr. Bucket himself never really believed that Mr. George was the murderer, and that Mr. George was jailed only because the circumstances didn't rule out the possibility that Mr. George may have been the murderer. Mr. Bucket alludes to Lady Dedlock and the distrust with which Mr. Tulkinghorn regarded her, angering Sir Leicester Dedlock. But Mr. Bucket continues, arguing that Lady Dedlock's role is at the heart of Mr. Tulkinghorn's murder. To that end, witnesses are produced. Indeed, their presence at Chesney Wold are presently heard before seen (Grandpa Smallweed is making a racket downstairs), prompting Mr. Bucket to ask Sir Leicester to have them brought before Sir Leicester. Sir Leicester consents.
Presently, Grandpa Smallweed, Mr. and Mrs. Chadband, and Mrs. Snagsby are suffered to enter the library. Grandpa Smallweed demands payment for the letters he had entrusted to Mr. Tulkinghorn, letters which originally belonged to Captain Hawdon and which were in Krook's possession. Assuring Grandpa Smallweed that the letters are in his--Mr. Bucket's--possession, Mr. Bucket then haggles with Grandpa Smallweed about his payment before informing Sir Leicester about the significance of these letters. They are letters between Captain Hawdon and his wife Honoria with regard the fate of their daughter whom Honoria believed to be dead and on which Honoria made the basis of her separation and divorce from Captain Hawdon. But as Mrs. Chadband testifies, the daughter is alive and well, and that previous to becoming Mrs. Chadband, Mrs. Chadband been in Honoria's sister's service in the role of Honoria's abandoned daughter's governess. The significance of this is that Honoria's true identity is Lady Dedlock, as Mrs. Chadband testifies.
According to Mr. Bucket, Mr. Tulkinghorn had been privy to all of the aforementioned intelligence, and it was only a matter of time before the lawyer would have disclosed it to Sir Leicester. Mrs. Snagsby attests to Mr. Tulkinghorn's integrity all the while complaining about a conspiracy against her which she believes her husband Mr. Snagsby has engineered. Presently, Mrs. Snagsby, Mr. and Mrs. Chadband, and Grandpa Smallweed are dismissed, and Mademoiselle Hortense, who is currently a lodger in the Bucket household, is brought to the library. Mr. Bucket explains that Mademoiselle Hortense had held a murderous grudge against Lady Dedlock since Lady Dedlock's dismissal of Mademoiselle Hortense (as her personal handmaiden). Subsequently, following Mr. Tulkinghorn's murder, Mr. Bucket had commissioned his wife Mrs. Bucket with the job of keeping a vigilant eye on Mademoiselle Hortense.
The day after Mr. Tulkinghorn's funeral, Mademoiselle Hortense had proposed to Mrs. Bucket that they go out to the country for tea. Mrs. Bucket had agreed, and while they were having tea, Mademoiselle Hortense excused herself only to return quite out of breath. Mrs. Bucket reported this to Mr. Bucket who subsequently found the murder weapon of Mr. Tulkinghorn, a pistol, which had been thrown into a pond that lay nearby the country tea house. Thus, it was Mademoiselle Hortense, who knew of the mutual animosity that existed between Lady Dedlock and Mr. Tulkinghorn, who had killed Mr. Tulkinghorn with the aim of framing Lady Dedlock of the murder. Presently, Mr. Bucket handcuffs Mademoiselle Hortense who is defiant.
Alone, by himself, Sir Leicester agonizes over this turn of events. He cannot believe that the one person for whom he had lived his life--Lady Dedlock--is now in disgrace. Still, towards her, he feels more compassion than reproach.