In this chapter, Quentin and Shreve really delve into Charles Bon's thoughts, trying to reconstruct his still unexplained thinking about his father (Sutpen) and his half-brother (Henry) and half-sister (Judith). In this chapter, too, Quentin and Shreve start to notice parallels between their quest for understanding and the quest that Henry and Bon were engaged in.
In this process of trying to understand Charles Bon, Quentin and Shreve invent a lawyer, someone who helps Eulalia (Charles Bon's mother) manage the money that Sutpen gave her and someone who might have his own plans for Eulalia's (and Sutpen's) money. This lawyer, they suggest, carefully plots and evaluates the best time and the best way to blackmail Sutpen with the information about his previous wife and his abandoned son.
They decide that Bon doesn't know that Sutpen is his father. They also decide that Bon doesn't know that Sutpen abandoned his mother because of her "negro blood," or that he also has "negro blood." He grows up not knowing, and he is sent to the University of Mississippi either as part of the lawyer's plan to encourage an incestuous engagement between Judith and Bon, or as part of the mother's plan to help him discover his father and his history. Bon is sent to college when he is twenty-eight, and he is sent to a remote university quite far from New Orleans; Quentin and Shreve imagine the lawyer explaining this recommendation as a way to broaden his experience and prepare him for a future leadership role in his community. The lawyer also writes a letter of introduction to Henry Sutpen, encouraging Henry to help Bon adjust to his new surroundings.
As Quentin and Shreve tell it, Bon figures out that Henry is his half-brother, partly through the physical resemblance, and partly through his own suspicions about the decision to send him to the University of Mississippi with a letter to Henry Sutpen, that Henry eventually shows Bon. He travels home to Sutpen's Hundred not to see Judith, though he has heard a great deal about her from Henry, but to see his father and, he hopes, see or hear his father's recognition of him as his son. Sutpen does not acknowledge that he knows Bon, and he doesn't acknowledge Bon as his son on any of the subsequent visits, either.
Shreve seems to be talking now, and he turns the conversation to Bon and Judith, and the relative unimportance of their connection. Bon is a wealthy, handsome, and polished young man with a mysterious background, and it would be difficult to imagine Judith finding a better opportunity. As Shreve puts it, Bon might be the first man to talk to Judith who doesn't have the scent of manure on him. Shreve stops his account long enough for Quentin to step in, and Quentin has nothing to say about love. Shreve continues the story, saying that Bon kept hoping that Sutpen would acknowledge him, imagining several small ways that Sutpen might signal his paternity, which Bon would accept as enough to make him drop his engagement. Still, Sutpen does not acknowledge that he knows Bon. Sutpen disappears for six months on business, and Bon tells himself that Sutpen has gone to New Orleans to make sure that he is the lost son. Bon returns home to New Orleans and is unable to find out if Sutpen has been there. The summer passes, and Bon returns to the University and Henry. They go back to Sutpen's Hundred for that Christmas, in 1860, and Sutpen summons Henry to see him alone. When the meeting is over, Henry leaves the house and departs for New Orleans with Bon.
Quentin and Shreve believe that Sutpen told Henry that Bon is his half-brother, and Shreve adds that Sutpen probably also said that Bon knew this the entire time, and that he made advances toward Judith knowing that she was his half-sister. Henry calls this a lie, but Quentin and Shreve think that the long ride to the steamboat that would take them to New Orleans probably meant that Henry was thinking about how this explained many things. They guess that Bon brought Henry to meet his mother, and perhaps his mistress and son. They also imagine a meeting with the lawyer, who now knows that Bon knows about his father and that Bon might be willing to blackmail his father. The lawyer makes a bad joke about Judith and Bon knocks him over and offers him a duel, which he refuses. At this point, Shreve suggests that the lawyer would get his revenge by killing Bon's mother, stealing her money, and running off to Texas or Mexico, leaving Bon's mistress and child behind to starve.
The lawyer's suggestion of blackmail confirms Bon's belief that Sutpen is his father. Shreve and Quentin think about what it must have been like that winter in New Orleans, knowing, because of the lawyer, that they were brothers and that Sutpen had told Henry the truth. They imagine the conversations between the two of them, Henry asking for time to get used to the idea, and the finding of precedent in the Duke of Lorraine, who married his sister.
Bon and Henry enlist with the University Grays partly because, as Quentin and Shreve see it, they hoped that the war would kill one of them and resolve the conflict for them. They suggest that Bon points out that Henry might get behind him in the lines and shoot Bon and pretend like a Union soldier had killed him. Shreve reverses the wounding that Mr. Compson suggested, and says that Henry is wounded, and rescued by Bon.
Bon and Henry enter the long, slow retreat with the Confederate Army of the West in 1865, and Bon decides to write the letter that Judith has been waiting for. He tells Henry, and Henry is thankful, mostly because it is a decision. Eventually, Sutpen's regiment is sent to join their group, and Bon sees Sutpen, though he can't make Sutpen acknowledge him. Sutpen asks Henry's commanding officer for a chance to speak to him, and he tells Henry about Bon's "negro blood."
Henry returns to his camp and finds Bon, who is awake. Bon quickly figures out what Henry has been told, and mentions that the "negro blood" appears to matter more than the incest. Bon says that he has given Sutpen four years to acknowledge him, but that he has decided that he must return to Judith and marry her now. Henry pleads with him to protect Judith, but Bon says that he is thinking of himself. Henry says that he will not marry Judith, and Bon asks who will stop him. Bon tells Henry to kill him now, and hands him a pistol. Henry throws it away.
Shreve suggests that Bon probably told Henry that he was leaving, and that they rode together across the country to Mississippi, Henry following Bon, and waiting as long as possible to kill him. Shreve ends the chapter with an explanation of the picture in the metal case that Judith finds on Bon's body - Bon put his mistress's picture in the metal case that Judith had given him so that if Henry killed him, Judith would have reason to think that he was a scoundrel and not worthy of grief.
This chapter resolves most of the flaws in Mr. Compson's and Rosa's accounts of the Sutpen family history, with mostly plausible explanations for some of the more challenging facts. The explanations that Quentin and Shreve offer in this chapter are sometimes endorsed by the text, such as the way that the image of Eulalia Bon is labeled "probably true enough," as if this last set of explanations are going to be accepted as the correct explanations.