Fogg finds prosperity in Effing’s final gift and chooses not to believe that his good fortune will end anytime soon. He moves into a new apartment with Kitty in Chinatown and spends an afternoon buying new clothes for both of them. Kitty takes on a summer job as a temporary secretary for a trade magazine. Fogg remains at home, taking care of the household chores, reading, and keeping a journal of his thoughts, which he plans to turn into esoteric essays.

Effing’s obituary is rejected by both the newspapers and the magazines. The magazines dismiss Effing’s story as a hoax, even after Fogg sends them a clipping of Julian Barber’s obituary. They conclude that even if Barber and Effing were the same person, there is nothing to suggest that he was a major artist worth commemorating. Fogg is reluctant to pursue the matter further, since it would entail looking for Effing’s paintings, which he has never seen and has preferred to imagine. While reading Tesla’s autobiography, Fogg comes across the same passage from his Moon Palace fortune, which he interprets as another sign of secret harmony in the universe. However, he fails in his attempt to write an essay on the topic.

Solomon Barber replies to Fogg’s mail and asks to meet him in New York. Solomon is a man with severe obesity. At their meeting, the two men quickly establish that Solomon was once a college instructor of Fogg’s mother, Emily. The narrative reveals that on Solomon’s deathbed, 10 months after their first meeting, he will reveal to Fogg that he is actually Fogg’s long-lost father. The narrator-Fogg explains that this is possible because Solomon and Emily had sex one night, causing a scandal that forced Emily to retreat to Chicago; after this point, it would have been impossible for Solomon to know that she had become pregnant. The narrative also reveals that Solomon was fired from his position as a history professor, and although Emily decided to keep her child, she refused to reveal the father’s identity to anyone, even Victor.

Solomon had enthusiastically pursued the chance to have sex with Emily when she offered it, since no one had ever been interested in him before on account of his weight. As a child, Solomon experienced bullying because of his size. He sought refuge in books and eventually graduated at the top of his class. After the army rejected him, he became a lauded scholar. Following the scandal with Emily and the loss of his job, Solomon remained in Cleveland and ate excessively, with the conscious desire to worsen his obesity. His ultimate hope was to expose enough people to his obesity so that he could internalize it and stop feeling pain over the way people treated him. When he began to lose his hair, he shaved off what remained and wore a variety of hats that became closely associated with his identity.

Leaving Ohio, Solomon started teaching in other schools and colleges in the Midwest, never staying more than three years in each state. On three occasions, Solomon crossed paths with Victor. One such occasion occurred at the New York World’s Fair, which Effing is also believed to have attended. The last occasion happened in Saint Paul in 1959, when Solomon saw Victor’s name in the newspaper and intuited his relation to Emily. Solomon reached out to Victor to verify his suspicion and promptly learned that Emily had died. Eager to learn more about Emily in the time since their last encounter, Solomon visited Victor to get more information, but he found that Victor had vacated his lodging with a small boy.

Hearing this story, Fogg retroactively understands that this was the reason Victor suddenly moved them to Chicago: He had realized that Solomon was Fogg’s father. Although Fogg resents Victor for having kept him from learning his father’s identity, he also understands that Victor was reluctant to part ways with him.

The narrative returns to Fogg’s first meeting with Solomon; the men meet again on each successive day of Solomon’s visit to the area, and they talk about Effing. Solomon reveals that he grew up under the assumption that his father died on his journey. He also explains that the trauma of this loss caused his mother to live in a state of semi-catatonia that made her unable to recognize Solomon. Consequently, their relationship became distant despite Solomon’s best efforts to spend time with her, and she eventually entered a psychiatric hospital in Switzerland. In Effing’s absence, Solomon spent much time admiring his father’s art collection, even organizing an art exhibit at one point.

Solomon relates to Fogg that near the end of high school, he wrote a novel entitled Kepler’s Blood, which engaged with his father’s disappearance.

Solomon goes on to describe the plot of his novel, which features an artist named John Kepler, who treks West and falls off a cliff. In the story, Kepler is rescued by an isolated Indigenous community calling themselves the Humans; they have blue eyes and red hair. The Humans came to Earth from the moon and bonded with another human group called the Others. Together, they faced the threat of a third group called the Wild Men, who tried to cut down the forests and used guns to kill their enemies. Many of the Humans retreated to avoid the Wild Men’s wrath, eventually settling in a desolate region called the Land of Little Water, where they continue to live.

Kepler learns the Humans’ language and becomes integrated into their society. He discovers that the Humans saved him because they identified him as the prophesied savior who would resolve their diminishing population issues. To this end, Kepler remains with the Humans and has sex with various women to give them children.

Meanwhile in Long Island, Kepler’s son, John Kepler Jr., sets out to find evidence of his father’s fate. Kepler Jr. arrives at the Humans’ encampment and recognizes the chief as his father. Kepler rejects Kepler Jr.’s assertion, which provokes the latter into killing his father in his sleep. The only witness to the murder is a young boy named Jocomin, who pursues Kepler Jr. for several days. He trains under a medicine man named Silent Thought to learn the magical art of the “Twelve Transformations.” After several years, Jocomin becomes the new chief and sets himself to resolving the tribe’s famine issues. He has a dream in which the issue will only be resolved if he avenges his father’s death. Jocomin goes into the world of the Wild Men and learns that Kepler Jr. has become a successful businessman. Rather than killing Kepler Jr., Jocomin abducts Kepler Jr.’s young son and takes him back to the Humans. However, the two learn that the Humans have died out in Jocomin’s absence. Jocomin resolves to raise Kepler Jr.’s son as his own, renaming him “Numa.” Several years later, Jocomin masters a “Thirteenth Transformation” and becomes a woman, having twins with the adolescent Numa.

Kepler Jr. realizes that his son’s abduction was revenge for Kepler’s death. He goes back to Utah to search for his son and ends up shooting a wild coyote one night. The novel ends with Kepler Jr.’s revelation that the coyote was none other than his own son, who had mastered the art of Transformation. A pack of coyotes arrive to kill Kepler Jr.

The narrator-Fogg asserts that for all of the faults of Solomon’s novel, it accurately captures Solomon’s feelings toward his absent father and foreshadows his career as an academic who studied adjacent subjects in history, such as the American West myth and white integration in Indigenous communities.

The narrator-Fogg continues to relate Solomon’s prior life story. In 1939, Elizabeth died, leaving Solomon the sole heir of his family’s estate. Unwilling to live in his parents’ house again, Solomon promptly bequeathed it to his Aunt Clara, who had helped to raise him after Elizabeth had moved to Switzerland. Solomon’s only request was that Aunt Clara bequeath the house to her Black cook, Hattie Newcomb, upon her death. Solomon then asked Clara about the search for his father’s remains and Elizabeth’s mental health crisis. Clara reluctantly revealed that the crisis occurred on the same night that Solomon was born. Believing that Solomon had been trying to kill her with his size, Elizabeth had tried to kill Solomon while she had been in labor.

On his last day in New York, Solomon thanks Fogg for listening to the story of his life, which he has never told to anyone else. They maintain correspondence after Solomon leaves, and Solomon sends Fogg the manuscript of his novel. At the start of the following year, Solomon returns to New York while on leave from work and invites Fogg and Kitty to his new apartment for dinner. During the dinner, Solomon wonders if Effing had been telling the truth about the Utah cave he resided in. Fogg posits that even if the cave didn’t exist, the story might have been true in an emotional sense. They all agree to search for Effing’s cave, though Fogg initially takes this discussion as a joke.

Two months later, Kitty gets pregnant, and her relationship with Fogg becomes tense when she decides that she wants to terminate the pregnancy. Kitty argues that a pregnancy would disrupt her life as an aspiring dancer because she would have to spend her time taking care of the baby. Fogg is reluctant to let go of the baby because he sees it as a chance to correct the lack of family in his life. Eventually, he relents and pays for Kitty to have the relevant procedures. Fogg’s grief over the baby’s loss prevents him from consoling Kitty as she recovers physically and emotionally. Despite Kitty’s pleas that he stay with her, Fogg leaves her out of guilt over his moral weakness.