Richard, a wealthy doctor, invites his estranged sister Angela and her family to join him for a week at a vacation home in the English countryside. Richard has just re-married and inherited a willful stepdaughter in the process; Angela has a feckless husband and three children who sometimes seem alien to her. The stage is set for seven days of resentment and guilt, a staple of family gatherings the world over.

Christopher John Francis Boone is a fifteen-year-old autistic savant obsessed with Sherlock Holmes. He knows all the countries of the world and their capitals and every prime number up to 7,057. He relates well to animals but has no understanding of human emotions. He cannot stand to be touched. And he detests the color yellow. This improbable story of Christopher's quest to investigate the suspicious death of a neighborhood dog makes for a captivating and unusual tale.