What does Christopher find while looking for his book

We are introduced to Christopher Boone, the novel’s protagonist, just as he has discovered the body of his neighbour’s dog. It appears as though someone killed it with a garden fork. Unsure of what to do but sensing that he should do something rather than just stand there, Christopher picks the dog up. Unfortunately, his neighbour spots him and screams before calling the police. 

When the police arrive, they attempt to touch Christopher, who feels a rush of anxiety and frustration and lashes out at them. He is taken to the police station and given a caution. 

The next day, Christopher determines to investigate what really happened to the dog and who is responsible for its death. His father sternly warns him against taking such a path, stating that people don’t appreciate others getting involved in business that doesn’t concern them. Christopher proceeds with his investigation in secret, doing what he can to hide it from his father. The investigation is recorded in a book – the one we are reading.

It does not take long for Christopher’s investigation to stray away from the death of the dog and towards his family’s history. One afternoon, after returning from school, Christopher accidently leaves the book in open view of his father, who reads it and reprimands him for not obeying his orders to mind his own business. After happening upon a shoebox filled with letters, he realises that his ‘dead’ mother may not be dead at all, as the letters are from his mother and addressed to him. Christopher’s father told him that his mother had died from a heart attack when he was younger. In fact, she now lives in London with Mr Shears, the family’s former neighbour – the two had an affair. Christopher faints in shock. 

Later that day, when Christopher’s father comes home, he breaks down as he confesses to his son that he was motivated by a desire to protect his son emotionally. He also reveals that he is the one who killed the dog. This revelation prompts Christopher to think that he is no longer safe at home with his dad, so he packs up his pet rat Toby and runs away. 

At the train station, Christopher buys a ticket to London. The experience is extremely challenging for him; he is especially tormented by the loud noises and volume of people bustling against each other.

Christopher’s mother is completely taken aback by his arrival in London, as she was totally unaware that his father had been keeping her letters from him. Christopher settles in at the apartment his mother shares with Mr Shears, but his presence puts a strain on the relationship, and his mother soon decides to leave London and return to Swindon without Mr Shears. 

In Swindon, Christopher moves into a new apartment with his mother, where his father regularly visits them both. Christopher’s pet rat Toby dies, and his father gifts him a puppy. At school, Christopher sits the A-level maths exam and scores the top mark possible. 

The novel concludes with Christopher stating that he plans to take more A-level exams before attending university in another town, to study to become a scientist. He knows he can do this “because I went to London on my own, and because I solved the mystery of Who Killed Wellington? And I found my mother and I wrote a book and that means I can do anything.”

• On Monday, Christopher goes back to school.
• Siobhan asks why he has a bruise on his face, and he tells her what happened. They talk about it for a while and then Siobhan asks if he's scared to go home again. Christopher says he isn't, and so they drop the subject.
• When he gets home from school that day, Christopher starts looking for his book. It isn't in the garbage can, so he looks all around the house. Eventually he's looked everywhere but his father's bedroom.
• He's very careful not to move anything, or else his father will know he was snooping around in there, which clearly won't make their situation any better.
• Finally, underneath a toolkit at the bottom of the cupboard, inside an old shirt box, he finds his book. Ta-da!
• At that moment, he hears his father's van pull up outside the house.
• Christopher knows he has to think fast. He figures that his dad probably won't throw the book away, so he doesn't have to worry about losing it.
• He'll start another book, and maybe get this one back one day when his father is less angry.
• Right when he hears the car door slam outside, he sees an envelope with his name, "Christopher Boone," written on the front.
• Then he sees there's a whole big stack of envelopes, all addressed to him. And the handwriting is all the same, with the letter I dotted with circles instead of dots.
• There are only three people he knows who draw circles above the letter I like that: Siobhan, another teacher, and his mother.
• He quickly takes one envelope from the stack and puts everything else back in the cupboard. This kid's a quick thinker.
• When his father calls his name, he doesn't answer: Christopher doesn't want him to know he's in his room. Instead takes the envelope into his room and hides it under the mattress before heading downstairs.
• His father makes him dinner and they're very nice to each other while they eat – it's really quite sweet.
• Then Christopher goes back to his room, shuts the door, and takes out the envelope.
• He wonders whether it's okay for him to open it: on the one hand, he took it from his father's room; on the other hand, it's addressed to him (not his dad).
• He opens it, and reads it.
• The author apologizes for not having written in so long, but she's been very busy. She writes about her new job working as a secretary in a factory, and about the new flat she and someone called Roger have moved into in London.
• She says she realizes that Christopher is probably still angry with her, but she would love to hear from him.
• And – here's the kicker – it's signed, "Your Mum."
• Gasp!
• Although we're starting to put the pieces together, Christopher is still confused, since his mother never worked as a secretary in a factory, and never lived in London.
• He looks at the postmark on the envelope, and sees that it was sent eighteen months after his mother died.
• Okay, now he's really, really confused.
• At that moment, his father walks in and tells him that one of his favorite TV shows is on, if he wants to come down and watch it.
• Christopher stays in his room and tries to figure out what in the world is going on.
• Then he gets really excited, because now he has two mysteries to solve. Sherlock Holmes, here we come!
• Christopher decides that the next time his father is out of the house, he'll read the other letters. But for now, he goes downstairs to watch TV. We totally approve.

One night, Christopher Boone finds his neighbor's dog dead in her front yard, with a pitchfork sticking out of it. Eek – we're off to an interesting start, that's for sure. Anyway, Christopher wonders who killed it, and decides to write a book in which he tries to figure it out, like a murder mystery novel.

Christopher has a disability – unspecified in the book, but which has been compared with an autism spectrum disorder called Asperger syndrome – that makes it difficult for him to understand social norms like body language and other forms of human interaction. He is, however, tremendously good at math and more logic-based skills (like writing a crazily-detailed daily schedule, or drawing intricate maps of places he's only visited once).

Christopher's neighbor, Mrs. Shears, finds him with her (now-dead) dog, calls the police, and Christopher has to spend a few hours in a jail cell. Eventually, his father comes to get him, and tells Christopher to not investigate the dog's death any further. So, in response, Christopher thinks of all kinds of ways to interpret his father's demand as specifically as possible… so he can still do all of his detective work while somehow not disobeying him.

He starts asking around the neighborhood to see if anyone knows anything about the dog's death. He decides that since Mr. Shears left his wife two years ago, perhaps he hates her, and killed her dog to make her sad. (Seems like a stretch, but you never know.) When Christopher's father finds out he's been asking people about the dog, he makes him promise he'll stop. Again. Christopher promises.

So, of course, Christopher continues talking to one of his neighbors, who tells him that his (Christopher's) mother and Mr. Shears were having an affair before he left Mrs. Shears. That's bad news. But Christopher tells her that his mother died two years ago, of a heart attack.

Christopher's father finds the detective book Christopher has been writing, in which he's recorded everything that has happened so far. He's really mad about it, and takes the book away. A few days later, Christopher searches the house for the book, and finds it hidden in his father's bedroom. But here's the kicker: he also finds a big stack of letters addressed to him, from his mother. He reads a few of them, and discovers that – wait for it – she's actually still alive! His father had been lying to him this whole time.

His father apologizes for lying, and also admits that he was the one who killed Mrs. Shears' dog. As it turns out, he has feelings for Mrs. Shears, and was mad that she didn't want to be with him. Whoa.

Christopher decides that living with his father is no longer such a great (or safe) idea – he is a dog-killer after all – and thinks it's best to move to London and live with his mother. Problem is, he's never gone anywhere by himself before, and has difficulty being in busy places and/or around large groups of people. The journey is, as we might then expect, incredibly challenging. First, after he runs away, his father enlists the police to try to find him. He manages to escape anyway, but then he's totally overwhelmed, being on his own like this. He repeatedly vomits and passes out and just feels horribly sick.

Hours and hours later, he arrives at his mother's apartment in London. She's living with none other than Mr. Shears. Christopher tells her that his father said she was dead, and she's horrified to learn this. When Christopher's father comes to find him, she demands he leave and insists that poor Christopher can live with her. But Christopher is afraid of Mr. Shears, and is quite eager to go back home to take an important exam that will help him get into university.

After about a week, he and his mom go back home, and Christopher takes the exam (even though he can't think straight, after not eating or sleeping for days on end). His mother gets a job and a not-so-nice apartment, which Christopher hates. Meanwhile, his father tries very hard to earn back his trust. He buys him a puppy (that's some brownie points right there), and Christopher begins spending some time at his house again.

He receives his exam results, and finds out that he got the best possible score. Having successfully traveled to London on his own, and solved the mystery of who killed the dog, he's sure he can do anything. We agree.