Christopher is 15 and lives in Swindon with his father. He has Asperger's Syndrome, a form of autism. He is obsessed with maths, science and Sherlock Holmes but finds it hard to understand other people. When he discovers a dead dog on a neighbour's lawn he decides to solve the mystery and write a detective thriller about it. As in all good detective stories, however, the more he unearths, the deeper the mystery gets - for both Christopher and the rest of his family.