Christopher awakens at Mother’s apartment. While he eats breakfast, Mr. Shears and Mother argue over how long Christopher can stay. Mother takes leave from work to care for Christopher. She takes him shopping for items he needs, such as pajamas, but she has to take Christopher home when he becomes frightened in a store. Christopher tells Mother he must return to Swindon to take his A-level math test, but Mother says she doesn’t know if that’s possible. That night, Christopher can’t sleep, so around 2 a.m. he goes out into the street and takes a walk. Mother comes out of the apartment shouting his name, scared that he has run away. She finds him and makes him promise never to leave the flat on his own again.
A few days later, Mother is fired from her job for taking leave. Christopher demands to be taken to Swindon to take his A-level test. Mother insists the test can be postponed. The next morning, Christopher tries to forecast the day by looking out the dining-room window. He sees five red cars in a row followed by four yellow cars in a row, invalidating his system. Mother takes him to watch the planes take off and land from Heathrow airport. She says she has phoned Mrs. Gascoyne to postpone his A-level test till next year. Christopher screams at the news.
Every night Mother and Mr. Shears argue. Christopher takes the little radio from the kitchen and leaves the tuner between stations so that the white noise drowns out their arguing and keeps him from thinking about the A-level test. One night Mr. Shears comes into the spare room and wakes Christopher up. Christopher can tell that Mr. Shears has been drinking. Mr. Shears accuses him of not caring about the people around him. Mother pulls Mr. Shears out of the room before he can say anymore.
The next morning, Mother and Christopher leave for Swindon, taking Mr. Shears’s car. Mother explains that if they stayed in London any longer someone would get hurt. In Swindon, they go to Father’s house. Christopher plays Minesweeper in his room. He hears Father arrive home from work, so he pushes his bed up against his bedroom door to prevent Father from entering. Mother and Father argue in the living room. Father leaves to stay with Rhodri for a few weeks. Christopher again begs to take his A-level test, but Mother has already postponed it. Christopher compares the feeling he gets at hearing this to holding your thumb against a hot radiator. That night, he does not eat and has trouble sleeping.
The next day, Mother takes Christopher to school. Siobhan tells Christopher that Mrs. Gascoyne still has his A-level test sealed on her desk, and that they are going to try to get Reverend Peters to come over so Christopher can take his test after all. Christopher feels excited but also tired from not sleeping the night before. That afternoon, Christopher begins his first section of the exam. He reads through it and has trouble thinking of the answers. He feels so frustrated that he wants to stab someone with his Swiss Army knife, but he counts prime numbers in his head to relax. Then he rushes to complete the test. That night, Father comes to the house again, so Christopher hides in the garden until Father leaves.
The next day, Christopher takes part two of the exam. That evening, Mr. Shears throws a large box of Mother’s belongings on the lawn, then gets in his car and drives away.
Christopher finishes the exam the following day. Father comes to the house that night and asks Christopher how the exam went. Christopher doesn’t answer until Mother prods him to. The following week, Father asks Mother to move out. She gets a job at a garden center and a doctor prescribes her medication for her depression. She and Christopher move into a room in a brick house that Christopher doesn’t like for many reasons, primarily that the bed is in the kitchen and that they share the toilet with strangers. He has to stay at Father’s house after school each day because Mother doesn’t get off work until 5:30 p.m. Christopher locks himself in his room so that Father can’t get in, and sometimes Father talks to him through the door but Christopher doesn’t answer. Toby dies of old age at two years and seven months. Christopher buries him in the soil in a plastic pot for plants because Mother’s house doesn’t have a garden.
One day after school Father sits Christopher down. Father says Christopher’s trust is more important to him than anything else. To start rebuilding that trust, Father gives Christopher a two-month-old golden retriever. Christopher names her Sandy. The puppy has to stay at Father’s house because there isn’t enough space in the one-room apartment Christopher shares with Mother, but Christopher can visit whenever he wants. The next week, Christopher learns he got an A on his A-level math test. He spends some nights in Father’s house and feels okay with Sandy sleeping on the bed. He plants a vegetable patch in the garden with Father. He buys a book to study his next set of A-level tests.
Christopher sets out a series of goals for the future: to get A grades in A-level Further Math and A-level Physics, so that he can attend university in another town, where he will live in a flat with a garden and a proper toilet with Sandy, his books, and his computer. He will graduate with a first-class honor degree and become a scientist. He knows that he can do all of these things because he went to London on his own, solved the mystery of who killed Wellington, found his mother, and wrote a book. And that means he can do anything.
Transition is a prominent theme in the book’s final chapter, as much of the chapter involves the characters adapting to new situations. Christopher, for instance, lives with his mother now and has to adjust to living in a new place without his father. He also loses his pet rat Toby, who dies of old age. Christopher’s mother and father, meanwhile, face their own challenges as they deal with the new way Christopher figures into each of their lives. Mother in particular has a hard time adjusting to having Christopher in her life again because of Christopher’s difficult behavior, as when he becomes frightened in the store and Mother has to take him home. The book suggests, however, that these hardships will lead to happiness for the characters. Christopher gets a new puppy to compensate for Toby’s death, for instance, and his mother begins to settle down with a new job, a new apartment, and begins to get help for her depression. Christopher and his father also plant a vegetable patch, which serves as a metaphor for how their relationship will eventually grow, suggesting even the rift between them will be repaired.
In the challenges Christopher’s mother faces with this transitional phase, the reader also sees the effect that Christopher’s condition has on his mother, giving the reader more insight into why she left Christopher and his father years before. Mother frequently feels frustrated by Christopher’s behavior and by his inability to sympathize with her or understand her position on an emotional level. She finds Christopher indifferent to her needs, for instance, when she tries to explain to him that she cannot take him to Swindon for his A-level math test. In taking care of Christopher, she additionally loses her job and frequently argues with Mr. Shears and Christopher’s father (the reader doesn’t see the arguments with Father for the most part, but Mother tells Christopher that he is threatening to take her to court). She appears overwhelmed by the stress, and we learn that she also suffers from depression, a detail Christopher mentions in passing when he says the doctor gave her pills to keep her from feeling sad. These details help clarify Mother’s decision to leave years earlier by showing how emotionally taxing she finds caring for Christopher, and as the novel concludes we see the sacrifices she makes to again become part of his life.
As the novel ends, Christopher talks about his goals for the future, demonstrating a greater confidence in himself and his ability to be independent that stems from his accomplishments over the course of the novel. Notably, Christopher’s plans for his future include living on his own. Although he doesn’t say so explicitly, the fact that he lists living in an apartment by himself alongside goals like becoming a scientist suggests that being independent would represent a significant triumph to Christopher. It also implies that he recognizes the ways in which his condition limits him. Christopher, however, says he knows he can accomplish these goals because of his recent achievements, specifically going to London by himself, solving the mystery of Wellington’s murder, acting bravely when he felt afraid, and writing his book. In other words, he has proven to himself that he can live—and thrive—on his own.
Despite the chapter’s suggestion that things will improve for Christopher and his parents, the chapter also reiterates the notion that disorder exists as an inherent part of life. Although Christopher and Father have made significant progress in restoring their bond, they still remain distant from one another when compared with how close they were at the start of the book, for instance. Moreover, Christopher no longer lives with Father, and he still distrusts Father to a large degree. Instead, he lives with his mother in a small, unpleasant apartment as Mother struggles, often with great difficulty, to reorder her life. His relationships with both parents remain fragmented since he doesn’t trust Father and hasn’t spent any significant amount of time with Mother in years. His parents also haven’t fully reconciled with one another by the novel’s close, yet both want to be present in Christopher’s life. Consequently, Christopher exists in an uneasy triangle with his mother and father. He appears joyful regardless, implying that disorder, while challenging at times, particularly for a character like Christopher who needs order and routine, doesn’t prevent happiness if one can learn to live with it.