Christopher Boone is a 15-year-old boy, who is suffering from Asperger’s syndrome. One day he finds his neighbour’s dog, Wellington, stabbed by a garden fork and he decided to try to solve the mystery, which he describes in this book . This takes him on an adventures journey which challenges him both physically and mentally. Christopher knows a great deal about mathematics, but understands very little about other human beings feelings and actions. He needs routine and order in this life, and the slightest changes in this daily life, makes him really upset. He hat being touched and loud noises, he can’t tell lies, he can’t understand or tell jokes, and he doesn’t understand sarcasm or irony. If something unexpected or scary happens, he has the tendency to crouch down, put his hands over his ears and groan loudly to try to shut all sound out.

Christopher lives with his father, in the belief that his mother died of a heart attach a few years earlier. His father is strongly against the book Christopher is writing, and confiscates it and hides it away in this bedroom wardrobe. While Christopher is trying to finds his book, he accidently discover a bunch of letters address to him from his mother, which is hard to understand and makes him puzzled. When his father comes home from work, he finds Christopher lying on his bed covered in vomit. He tries to explain to Christopher that he lied to him about his mother’s death, to try to protect him from getting hurt, and he also tells him that he had killed Wellington after a heated argument with his owner. This makes Christopher frighten and he decides run away to his mother, who lives in London. After a long and frightening journey he finally manage to get to London, where his mother takes him in, but is so followed by his father, who tries to convince him to come back, but Christopher is still too frighten. After an argument between Christopher’s mother and her boyfriend, which leads to their break up, she decides to take Christopher back to his father. She moves into an apartment, while Christopher’s father tries to win back Christopher’s trust, among other things by buying him a pet dog to replace his rat, which died. Christopher passes his A-level math test with top grads, and whiles the relationship between him and his father slowly rebuilds, he is optimistic towards his further because he went to London on his own, because he solved the mystery of Who Killed Wellington and he was brave ad wrote a book, and for this reason the believes that he can do anything.