The plot is conveyed from the points of view of the main characters in the novel.
Jacob Hunt is eighteen years old and has Asperger's syndrome, which is a form of high-functioning autism. He lives with his mother and brother, Emma and Theo Hunt, and lives by a structured schedule, feeling comfortable only when all of his daily activities are planned. Any lack of structure or unexpected events cause him to feel anxious. He is obsessed with forensic analysis; the hobby consumes his life. The novel opens with Jacob setting up a crime scene (in which he is the victim) for his mother to solve. Jacob's need to engage in such activities, as well as his obsession with detail, often frustrates his mother and infuriates his brother Theo.
Jacob Hunt - Eldest son of Emma and Theo's brother. He has Asperger's syndrome and he is accused of murdering Jess Ogilvy, his social skills teacher.
Emma Hunt - Single mother of Jacob and Theo Hunt. She works as a columnist for their town's local newspaper. She has devoted herself to her eldest son, Jacob, as a consequence of his disability. She creates "House Rules" which stipulate the following rules: Clean up your messes, tell the truth, brush your teeth twice a day, don't be late for school, and take care of your brother; he's the only one you've got.
Theo Hunt - 15 year old brother of Jacob, claims himself to be independent and rebellious. 
Rich Matson - The lead detective on Jess's case.