Christopher is a very intelligent, fifteen-year-old boy. He knows every prime number up to 7057 and all the countries of the world and their capitals. But he has no understanding of human emotions, because he is autistic. He has some strange quirks, cannot stand to be touched and it’s not exactly easy for his father. Christopher’s mother died two years ago. He lives with his father and Toby (his pet-rat) in their house in Swindon. Their neighbour Mrs. Shears sometimes comes and helps them with the housework.
Then one day, Wellington, Mrs. Shears’ dog, is killed with a fork and she suspects Christopher, because he finds the dog.
But it wasn’t Christopher who killed Wellington.
Although his father tells Christopher to keep his nose out of other people’s business, he tries to find out who killed the dog.
Christopher begins to write a book. He wants to solve the murder in the style of his favourite logical detective, Sherlock Holmes.
So he asks the neighbours if they’ve seen something unusual, if they like dogs and things like that and it’s not easy for him because he doesn’t like talking to strangers.
When his father finds out that Christopher writes a book he takes it away from him. Christopher looks for the book when his father isn’t at home and he finds it in his father’s room in a box. In this box he also finds 43 letters which were all addressed to him and so he reads the letters.
The letters are from his mother. At first he can’t understand it but then he sees that his mother not had a heart attack. She had not died. And his father had lied about this. He felt sick and giddy.
Mr. Boone comes home and finds his son lying on his bed. When he sees the opened box he understands what has happened. He is very angry but then he confesses that he had killed Wellington, because he thought Mrs. Shears cared more for her dog than for him and Christopher.
Christopher’s mother had an affair with Mr. Shears and two years ago they went to London, now they live there together.
Mr. Boone told his son that his mother had a heart attack.
Christopher is afraid of his father, because he lied and killed a dog. He doesn’t want to live with him anymore. He decides to go to London and live with his mother.
He comes back to Swindon to do his maths A level.
His mother gets a job and they live in a small flat. In the afternoon when his mother works he stays at his father’s house, because he isn’t allowed to be on his own.
Christopher doesn’t want to speak with his father, but one day his father gives him a dog, a golden retriever, and says that he wants that Christopher learns to trust him. The dog stays at the house, because the flat is too small, but Christopher can always come and take him for walks.
Christopher wants to take A-level further maths and A-level physics. Then he wants to go to university and become a scientist.