The morning after Christopher arrives at his mother’s flat, he has breakfast with her and Mr. Shears. Mr. Shears talks about Christopher as though he can’t hear, saying that it’s not going to work for him to stay there long-term. Judy, on the other hand, says that Christopher can stay as long as he wants, and she takes leave from work.
Mr. Shears exhibits complete disrespect for Christopher, hardly acknowledging him as a person and clearly not wanting him to mess up the life Mr. Shears has made with Judy. Judy, however, has always had good intentions and wants to make amends for her earlier lapses in parenting.
Judy and Christopher go to a department store to get him new clothes, but there are too many people, so Christopher lies on the floor and screams. Judy takes him home in a taxi, then goes back out to get what he needs.
This scene recalls almost exactly a scene Judy wrote about in her letter, one of the situations that made her feel like an inadequate mother. This time, however, she doesn’t let it visibly discourage her, although Christopher seems to be reverting to a younger self.
When Judy comes home, Christopher tells her that he has to return to Swindon to take his Maths A level. Judy is impressed he’s going to take the test, but she isn’t sure whether he’ll be able to go back for it.
Christopher’s desire to take the test means he feels able to think about the future again, but it’s still uncertain if he can even take the test he’s looked forward to for so long as his first step to adulthood.
That night, Christopher looks for the stars, but there are too many clouds and too much light pollution. He can’t sleep, so he goes outside and walks down the road. When he hears people coming, he hides behind a car. He stays there even when the people are gone, and he imagines a pattern of crosses in his head. Eventually his mother runs shouting down the road, and when she finds him, she makes him promise not to go out on his own again.
If he can’t see the stars, Christopher can’t position himself in the universe the way he usually does. His world is off-kilter, and he’s obviously not comfortable in his new home. Meanwhile, Judy finds herself having to face the stresses of parenting that Ed has dealt with since she left.
Christopher spends the next day in the flat. The day after that, Judy gets fired from her job. Christopher reminds her that he has to take his A level, but Judy is trying to deal with both Ed and Roger’s anger, and tells Christopher that he’ll take the exam later. Christopher is very worried about not being able to take it.
Christopher has completely thrown off Judy’s life with Roger, and she doesn’t understand the importance of the exam to him. Now that he feels safe, Christopher seems to have forgotten the urgency with which he left Swindon, and in his need for everything to go as he expects it to, he only wants to go back to keep the appointment for the exam.
The next day, Christopher tries to tell what kind of day it will be by watching the cars outside the window, but it doesn’t work because he’s not on the bus, so he can see as many cars as he wants if he waits long enough.
Christopher’s rules no longer work, symbolizing the further collapse of the world as he knows it. The cars acted as a sort of fortune-telling device, so the fact that they have failed means he is entirely unsure of his future.
That afternoon, Christopher’s mother takes him to Hampstead Heath, a park. She tells him that she’s called the school principal to cancel the A level. Christopher screams until a man comes to make sure everything is all right.
To prove the unpredictable nature of Christopher’s future, he no longer even has the A level to look forward to. The exam has been a fixture of his future for the entire book. Furthermore, it seems like another betrayal of trust for Judy to cancel the exam that meant so much to him.
The day after, Judy has Mr. Shears get Christopher some books about science and math, but they’re all too simplistic for Christopher. He hasn’t been eating, so Judy makes a game out of drinking a shake. When Judy and Mr. Shears argue, Christopher listens to loud static on a radio to block it out. The next night, Mr. Shears comes into Christopher’s room drunk and gets angry with him for being selfish. Judy makes Mr. Shears leave the room.
Christopher’s identity is structured around his logical mind and his mathematical abilities, but Judy and Mr. Shears can’t effectively relate to this part of him. The flat isn’t particularly safe or supportive for him, with Mr. Shears around. Christopher again seems to revert to childhood by refusing to eat, another issue that Judy wrote about in her letters.
The morning after this, Judy packs two suitcases, and she and Christopher take Mr. Shears’ car and drive to Swindon, because Judy thinks someone was going to get hurt if they stayed in the flat. On the way to Swindon, they get stuck in a traffic jam, and Christopher tries to create a mathematical formula to govern traffic jams.
Judy finally makes the right decision for both herself and Christopher by leaving Mr. Shears and retracing her path to Swindon, effectively retrenching herself in Christopher’s life. Meanwhile Christopher tries to put his life back into a controllable order through math.
When they get to the house in Swindon, no one is home. Christopher plays computer games, and his time is far worse than his best time. In the evening, Ed returns home. He and Judy have a shouting match while Christopher bangs on drums to drown it out. Eventually Judy comes up and says that Ed has gone to stay with his friend Rhodri. Christopher finds Toby’s cage and puts him back inside. Then he asks Judy if he can still do his Maths A level, but she says that it’s already been cancelled. Christopher is so upset that he doesn’t eat or sleep.
Christopher’s poor computer game time shows his serious inner turmoil, particularly since he played quite successfully after coming home from jail at the beginning of the book. He replaces Toby in his home just as Christopher himself has been brought home. However, his world is still upside-down. His mother has taken his father’s place, and he still can’t take his exam. Judy doesn’t seem to understand quite how important it is to him.
The next day, Judy and Christopher are about to get in the car to go to school when Mrs. Shears emerges to insult Judy. They drive away quickly. At school, Judy explains to Siobhan that Christopher is upset about the exam. Christopher draws a picture of a bus. After lunch, Siobhan tells Christopher that she’s spoken to Mrs. Gascoyne, and he might still be able to take the exam. Christopher is very tired and can’t think too well, but he decides he wants to take the exam anyway.
Tensions are high in all quarters, and Judy is essentially getting no support, but only anger. Siobhan, who always seems to understand Christopher better than almost anyone, manages to right his world by making the exam possible after all. Even though he feels he’s at a disadvantage, Christopher nonetheless needs to go through with this to continue into the future of his imagining.
Reverend Peters comes that same afternoon to proctor the exam. When Christopher first looks at the questions, he can’t figure out any of them. He wants to hit or stab Reverend Peters, but he can’t because then Reverend Peters wouldn’t proctor the exam. Instead, Christopher takes deep breaths and cubes numbers to calm himself. He finishes the exam.
It is ironic that Reverend Peters, who stands for everything Christopher thinks illogical, proctors an exam based on logic and method. The self-control that Christopher had to learn on his journey becomes useful here, as he keeps his temper and uses strategies to focus.
That evening, Ed comes back to the house. Christopher is frightened, so he lies out in the yard and looks at the stars. Ed comes outside, watches Christopher, and punches the fence.
Christopher is still afraid of his father, but at least he’s back where he can see the stars and position himself in the world. Ed still feels angry and frustrated about the situation.
The next day, Siobhan helps Christopher relax before he takes the next part of his exam. That night, Mr. Shears comes to the house, throws Judy’s belongings onto the sidewalk, and takes his car. As Mrs. Shears watches, Judy throws a box of cereal at the retreating car.
The life Judy made for herself apart from Christopher and Ed comes to an end with this complete break from Mr. Shears. Furthermore, Mrs. Shears sees that her ex-husband has failed both her and Judy.
The following day, Christopher takes the last part of his exam. He wants to write how he solved his favorite question, but Siobhan tells him it isn’t very interesting for his readers. He feels better because he’s finished the exam, but he’s worried because it’s possible the examination board won’t accept it, since the exam was temporarily cancelled.
Christopher enjoys math so much that he wants to share his love of it with anyone who might read his book, and he can hardly imagine that other people don’t love it as much as he does. But even though he’s gone through the stress of the exam, it still might have all been for nothing.
That evening, Ed comes to the house to ask Christopher how the exam went. Judy pleads with him to answer Ed’s questions, so Christopher tells him he’s not sure how well he did because he was tired. Ed tells Christopher he’s very proud of him.
Ed understands better than Judy how important the exam is to Christopher. The fact that Christopher finally speaks to his father indicates the beginning of a reconciliation.
The next week, Ed tells Judy she has to leave the flat, but she doesn’t have the money to do so. Christopher wants to know if the police will arrest Ed for killing Wellington, but Judy says they only will if Mrs. Shears presses charges. Finally, Judy gets a job and begins taking anti-depressants. She and Christopher move to a new house, but Christopher doesn’t like it because it smells strange.
Even if Christopher’s fear of Ed is beginning to lessen, he still thinks that Ed deserves punishment, demonstrating the equal value he places on human and animal lives. Christopher’s life changes again, and neither he nor his mother are very happy.
Christopher is worried about his exam results. He doesn’t know what the future holds. Siobhan tells him to try not to think about the future. Judy buys him a puzzle for which he has to figure out how to detach two halves of a cylinder from each other. He also helps her paint her room, and he ends up having to cut paint out of his hair.
Christopher always likes to know what to expect from any situation, but the uncertainty of his exam results, plus the changes in his home life, make it particularly difficult to know what to expect of his future in general. Judy manages to connect with Christopher’s logical side through the puzzle.
Christopher has to go to his father’s house after school, before his mother finishes work. He pushes his bed against the door so that Ed can’t get in, and he doesn’t answer when Ed tries to talk to him. Sometimes Ed sits outside the door for a long time. Toby dies of old age, and Christopher has to bury him in a pot because his mother doesn’t have a yard. He also solves the puzzle.
Christopher slowly moves forward in reconciling with his father. Even if he still distrusts him, at least he’ll consent to be in the same house with him. Ed obviously struggles with this. Toby’s death marks the end of an era of Christopher’s life, and Christopher makes sure to take care of his friend even in death.
One day, when Judy comes to pick Christopher up at Ed’s house, Ed asks to talk to Christopher. Christopher doesn’t want him to, but Ed sets a timer for five minutes and starts talking. He tells Christopher how much it hurts to have him in the house but refusing to talk or trust his father. Ed says it’ll be their project for Christopher to spend time with him, and for him to prove himself trustworthy. He reveals that he’s gotten Christopher a present, and brings in a golden retriever puppy. The dog will stay with Ed, and Christopher can come take him for walks.
Ed finally decides that they can’t go on with Christopher fearing him. He acknowledges that they both have to work to improve their relationship, rightfully implicating himself in the unpleasantness as well as Christopher. By giving Christopher a dog, Ed symbolically atones for his killing of Wellington. As dogs represent physical and emotional safety throughout the book, the gift also shows Ed’s desire to make his house a safe space for Christopher, rather than a frightening one.
The next week, lightning hits a tree near Ed’s house, and men cut it up and take it away. Christopher finds out he got an A on his Maths A level, and he’s very happy. He names the dog Sandy and takes him for walks. When Judy gets sick, Christopher spends three days at Ed’s house, but he doesn’t mind because Sandy is there to protect him. He even plants a vegetable garden with Ed.
Christopher’s life continues to change as even the landscape of his neighborhood changes. With his good test result, he has achieved a major goal, and his future seems more sure again. Furthermore, his relationship with Ed is improving, thanks in part to the safety that the dog provides.
Christopher buys a book to study for the next A level test in math, and he plans to take A level Physics after that. Then he’ll go to university and bring Sandy, and he’ll become a scientist. He’s sure he can do all this because he went to London all alone, he solved the mystery of Wellington’s death, he found his mother, and he wrote a book.
At the end of the book, Christopher looks toward his future with excitement and pride. He feels confident that he can achieve his dreams because he has overcome so many seemingly impossible obstacles. He has grown up, and this ending is a triumphant one.