Early the next morning, Byron has to run back to Hightower's house because Lena has gone into labor. Byron never made arrangements with a doctor as he had said he would, so he sends Hightower to go help deliver the baby while he goes to town to see if he can find a doctor. By the time the doctor arrives, Hightower has already successfully delivered the baby. Byron walks in the door and, upon hearing the baby cry, runs out and leaves on the mule. The actuality of the baby's birth has finally driven home the fact that Lena is not a virgin, and that Lucas Burch does in fact exist. Hightower walks home, resenting Byron, and makes himself a hearty breakfast before going outside to read Henry IV. He feels proud of himself for having successfully delivered the baby when the doctor and Byron were both too late, and he allows himself to enjoy the sense of pride even though he knows it is sinful. After napping he goes back to the cabin to see Lena, and he learns from her that Doc Hines snuck out while Mrs. Hines was asleep, and that Mrs. Hines then left to go after him. He also tells Lena that the best thing for her to do would be to leave Byron, so that he would not have to give his life to a woman who has already lived so much more than he has, but Lena starts crying because she believes that Byron has already left her.
Hightower is glad to hear this, but he checks at the mill to make sure, and he hears that Byron has indeed quit his job. Byron went to town to see the sheriff about allowing Lucas Burch to go to see his newborn son, but he has to wait while the special hearing of the Grand Jury to indict Christmas is underway. He goes to Mrs. Beard's boarding house to tell her that he will be leaving Jefferson, but she figures it all out before he says anything. Byron tells the sheriff the whole story, and he agrees that he will have a deputy take Lucas out to see Lena, without telling him where he is going. Byron hides outside the cabin until he sees Lucas go in, and then he takes his suitcase, gets on his mule, and starts out of Jefferson.
After cresting a hill, he stops for a moment to look back at the cabin, and as he watches he sees Lucas climb out of the back window of the cabin and start to run away. Without even really thinking about it, he suddenly knows that he has to do his best to chase Lucas down and fight him, so he goes after him. The deputy had taken Lucas to the cabin with the promise that his reward would be waiting for him there. When he walked in and saw Lena, she was completely calm, but he panicked. He strung together some half excuses, but she eventually put him out of his misery by saying that he must be busy. He grabbed at the chance to leave, and escaped through the window.
Lucas runs two miles to the train tracks, then finds someone who will take a message to the sheriff for him. Byron runs into this messenger, who tells him where he can find Lucas. Byron comes up behind Lucas, but he warns Lucas before hitting him, and so Lucas, who is the taller and more vicious man, quickly bests him. Lucas runs away while Byron recovers, and when a train passes, Byron sees Lucas jump on. Byron starts to walk, and a wagon soon passes him. The driver tells him that Christmas was killed in town about an hour ago. He had escaped from the prison and ended up hiding in Hightower's house, where he was found.
Gavin Stevens, the highly educated District Attorney, has his own theories for why Christmas chose Hightower's house as a place of refuge. He explains to his friend that he believes that when Mrs. Hines went to the jail to see Christmas, she had started to have hope that she could save him, and so she told Christmas about Hightower. Gavin believes that because of this Christmas saw Hightower as his last chance for salvation, and so he ran to his house. His theory is that Christmas's white blood tried to save him, but his black blood made him hit Hightower over the head with a pistol and then desert him, leaving him under a table where he let himself be shot to death without ever firing his pistol.
A young captain in the State National Guard, Percy Grimm, has become convinced that he needs to lead a squadron to maintain peace and prevent anyone from lynching Christmas. Neither his commander nor Sheriff Kennedy thinks it is a good idea, but Grimm is so determined that they cannot stop him. While the police move Christmas to the courthouse, he suddenly bolts away, and Percy Grimm immediately gets in on the chase. He spots Christmas rather quickly, and follows him through a small cabin to Hightower's house. Grimm and the other men that follow him find Hightower lying bleeding on the floor, but he does not tell them where Christmas is. Grimm somehow knows to find him in the kitchen, and he empties his gun into Christmas before the other men can follow him. When they enter, they see Grimm kneeling in front of the still-living Christmas, castrating him with a butcher knife. Christmas lies silently staring for a moment, before the blood gushes out of him and he dies.
Chapters seventeen through nineteen of Light In August focus on the process of storytelling itself. The problems of perspective and knowledge come up throughout the novel, but this section really ties these problems into the general problem of storytelling. The most climactic scenes of the novel are housed in this section, and yet the narrator is suddenly much more distant from the action, and the reader is told everything from novel perspectives.
Throughout the book, the story rarely moves forward chronologically, and so the reader learns many facts out of order. This is also true with the main protagonist's death, which the reader learns of before the scene describing the death takes place. Not only is the news of Christmas's death out of order, but it also comes from the mouth of a stranger, a wholly incidental character. A more detailed account of the death scene follows, but it comes from another new character, who is something of a parody of the intellectual upper class and whose understanding of Christmas's death is clearly colored by racism. Only then does the narrator himself recount the violent tale of Christmas's death in full. The narrator, however, conveys this part of the story through yet another new character: the racist, militaristic, and not at all likeable young man who is the one to kill Christmas. Thus when the reader finally gains a sense of confidence in the storyteller, the story is still filtered through an unreliable source. This powerfully underscores the unreliability of the narrator throughout the whole novel.
Gavin Stevens' account is especially problematic, for he uses the same kind of language and sentence structure as the narrator does, and it is abundantly clear that almost everything he says is an assumption based on almost no evidence. Gavin Stevens' account not only serves to highlight the fact that no narrator is ever without a specific perspective that colors the story, but it also underscores the absurdity of Christmas's racial identity crisis. Stevens is convinced that in Christmas's final flight, his white blood and his black blood were at war with each other, causing him to act in remarkably different ways. The absurdity of his belief, not to mention its virulently racist underpinnings, casts a new light on the powerful importance that Christmas, and everyone he ever met, placed on his racial identity.
Stevens' belief that Christmas's white blood compelled him to seek spiritual salvation in Reverend Hightower, while his black blood compelled him to strike the minister down, is clearly ridiculous, yet it reminds the reader of all of the other assumptions made about this character based on his white or black blood. Christmas himself tries to "inhale" blackness so that he can stop being split between two worlds, and the entire town of Jefferson bases the assumption of his guilt on his blackness. In the absurdity of this reasoning, it becomes clear that Christmas's tortured quest for a racial identity has nothing to do with his race in itself, but only on societal perceptions of identity.