Dick and Perry are in a small boat off the Mexican coast. They have befriended a rich German tourist named Otto, who has taken them out fishing. Perry sings and plays guitar, while Dick complains of a headache. It is Otto's last day, and the now-penniless killers will soon return to Mexico City. Just as the sun begins to set, Perry catches a giant sailfish. He is photographed with the fish, and he looks like he has arrived in the promised land.
Mr. Helms is still keeping up the grounds of the Clutter farm. One afternoon, he thinks he sees a face in Bonnie Clutter's window. He calls the police. They find Jonathan Daniel Adrian, a vagrant who has been living in the house. He has a shotgun and a hunting knife in his car, so he is arrested.
Dick and Perry are living in a hotel in Mexico City. They have run entirely out of money and must leave the hotel by 2 p.m. to avoid another day's charges. Perry must decide what to take with him on the bus back to America. Since Olathe, he has been moving around with two large boxes of personal effects. They hold tacky souvenirs, old letters, and notebooks. He sorts through them, picking out things to take. He finds a letter from his father, Tex John Smith, essentially a biography of Perry's childhood sent to the prison to help him get an early parole. In it, his father emphasizes that Perry was a "normal" child, and that he is "goodhearted" if he is treated right. He says that Perry does have a tendency to rebel against authority.
The letter, especially the way it leaves out certain details and is generally self-righteous, fills Perry with self-pity, love, and hate. Perry remembers watching his parents, "Tex & Flo," ride bucking horses at rodeos. He remembers his parents' divorce, how he went to stay with his mother and tried to run away to his father but was turned away. He remembers ending up in a Catholic orphanage, where nurses beat him because he wet the bed. Finally, his father took him in and he finished the third grade, the last schooling he ever got.
His father built a mobile home and the two traveled the country together. Perry joined the merchant marine when he was 16 and the army after that. He was on his way to join his father in Alaska after finishing his service, but a motorcycle wreck delayed him in Washington State for a year. He helped his father build a roadside lodge, but it never gained much business. He and his father began to starve, and they have a falling out over the last biscuit. He headed for Massachusetts, where he planned to meet up with an old army man, but along the way he fell in with "bad company" and robbed an office supply store in Kansas. They were arrested, but Perry escaped in a stolen car. He went to Massachusetts, but failed to find his friend. He moved to New York for a while, but eventually the Federal Bureau of Investigation caught up with him and brought him back to jail in Kansas--where he met Dick. By this time, his mother had died, his brother Jimmy had killed himself, and his sister Fern had "fallen" out of a window. He finds a letter that his remaining sister Barbara wrote him while he was in jail. It scolds Perry for feeling sorry for himself and for blaming their father and his childhood for his troubles. Perry loathes his sister.
Perry also finds an interpretation of his sister's letter, written by his prison friend Willie-Jay. In quasi-intellectual language, Wille-Jay writes that Barbara is obviously a conformist. He writes that it shows she is full of human frailings. The interpretation is full of quotations from Barbara's letter. Perry also finds some of his own notebooks. One is a "dictionary" of odd words that Perry has learned, such as "Thanatoid" or "Depredate." Another is a kind of diary that includes odd facts and quotations. All this time, Dick has been making love on the other bed to Inez, a prostitute he has promised to marry.