The Curious Incident of the Dog in the Night-Time recap

Christopher Boone, a fifteen-year-old in Swindon who is gifted at mathematics but finds people and change bewildering, discovers his neighbor's dog Wellington killed with a garden fork and sets out to solve the crime, recording it as a detective book. His father, who raises him alone and has told him his mother died two years earlier, orders him to stop investigating, but Christopher keeps going. Talking with neighbors, he learns that his mother had been involved with a neighbor, Mr. Shears. Searching his father's room, he finds a hidden cache of letters proving his mother is alive and living in London: his father lied about her death. Confronted, his father breaks down and confesses that he himself killed Wellington in a fit of rage after quarreling with Mrs. Shears. Terrified of the man who both lied to him and killed the dog, Christopher runs away, enduring a frightening solo train journey across the country to reach his mother, who has been living with Mr. Shears. He stays with her as that relationship falls apart, and she brings him back to Swindon. He sits his mathematics A-level and earns top marks, and his father slowly begins to rebuild his trust, starting with the gift of a puppy. Christopher ends convinced he can do anything.

One night in Swindon, fifteen-year-old Christopher Boone finds his neighbor Mrs. Shears's dog, Wellington, dead in her garden, killed with a garden fork. Standing over the dog when a neighbor calls the police, Christopher is briefly caught up in the confusion and, unable to bear being touched by a policeman, lashes out. Fascinated by the mystery and encouraged by his teacher Siobhan to record it, he resolves to find out who killed Wellington and to write the whole investigation as a book. He begins interviewing the people on his street, describing along the way how his mind works, how he loves prime numbers and hates being touched, and how his father raises him alone. His father is uneasy about the questioning and tells Christopher firmly to leave the matter of the dog alone.

Christopher keeps investigating in secret, his confidence growing even as his father's warnings sharpen. He talks with an elderly neighbor, Mrs. Alexander, who gently tells him things about the past that unsettle him, including that his mother had been close with the neighbor Mr. Shears before she was gone. Christopher continues recording everything in his book, which he hides. When his father discovers the book and reads it, he is furious that Christopher has ignored him and been prying into the family's affairs, and the two clash. His father confiscates the book and hides it. Searching for it, Christopher begins going through his father's things, sensing that the tidy story he has been told about his family does not quite hold together.

Hunting for his confiscated book, Christopher finds a hidden stash of letters in his father's room, all addressed to him and written by his mother, Judy, and dated well after the time she supposedly died. Reading them, he realizes with a shock that his mother is alive and has been living in London, and that his father lied to him about her death: she had left the family and gone away with Mr. Shears. The discovery overwhelms Christopher completely. When his father finds him with the letters, he confesses the lie and, in his remorse, admits a further terrible truth: it was he who killed Wellington, in a rage after a bitter falling-out with Mrs. Shears. Now certain his father has both lied to him and killed a living thing, Christopher becomes deeply afraid of him and decides he can no longer stay in the house.

Determined to reach his mother, Christopher runs away from home to travel alone to London, taking his pet rat Toby with him. For a boy who is terrified of crowds, noise, strangers, and being touched, the journey is an ordeal: he has to work out the trains, endure a chaotic and frightening station, evade a policeman, and push through panic and sensory overload at every stage, using his logic and his rules to keep himself together. After a long and harrowing trip, he finds his mother's address and arrives at the flat where she lives with Mr. Shears. Judy is astonished and moved to see him and takes him in, but Christopher's sudden arrival strains her life there, and tension mounts between the adults over what to do with him.

Christopher's presence proves too much for his mother's relationship with Mr. Shears, which falls apart, and Judy chooses her son over that life, taking Christopher back to Swindon. He is still frightened of his father, who now has to begin rebuilding their relationship from almost nothing, promising never to lie again and giving Christopher a puppy, Sandy, as a sign of good faith. Amid all the upheaval, Christopher sits the mathematics A-level exam he had fought to be allowed to take, and he earns an A, the top grade. The book ends on hope: Christopher intends to take more exams, attend university, and become a scientist, and he draws strength from everything he has come through. Having solved the mystery of the dog, uncovered the truth about his family, and made the journey to London and back on his own, he concludes that he can do anything.

Christopher's investigation of a dead dog uncovers the truth about his own family: his mother, Judy, is alive, and his father lied about her death to spare him the fact that she had left them for the neighbor Mr. Shears. When Christopher also learns that his father killed Wellington, his trust collapses and, frightened, he flees to London and his mother. That reunion is not a simple happy ending. His mother's life with Mr. Shears breaks down under the strain of caring for Christopher, and she chooses her son, returning with him to Swindon. Christopher and his father must begin again from almost nothing; his father works patiently to earn back Christopher's trust, promising never to lie to him and giving him a golden retriever puppy, Sandy, as a first step. Christopher sits his mathematics A-level, a goal that mattered enormously to him, and achieves an A grade, proving to himself what he is capable of. The book closes on a note of guarded optimism: Christopher plans to take further exams, go to university, and become a scientist, and he believes that because he solved the mystery, traveled to London alone, and did all of this despite everything that frightens him, he can do anything he sets his mind to.