Emmett is a popular junior at Heart High School. He also happens to be a highly imaginative twelve year-old child prodigy. After his brother Luke, also a junior and Emmett's best friend, is accused of being involved in a rash of thefts at the school, Emmett must find a way to prove his innocence before their mom ships Luke off to boarding school. Emmett enlists the help of his sixty-something SAT tutor and crime novelist, Mary, to help him find the real culprit. Together, with the assistance of his oddball friends and a benevolent science teacher, Emmett and Mary prove Luke's innocence and discover the real criminal may be someone from Mary's past.