The book is about Jacob, a teenage boy with Asperger's syndrome (autism). He is unable to follow the train of thought of other people and cannot express himself normally. Like most children with this condition, Jacob is focused on just one activity; in this case it is forensic analysis. He always ends up at crime scenes (with the help of a police scanner installed in his room), where he tells the cops what they should do... and he's always right. Each individual chapter of the book is narrated to us by the main characters: Emma, Jacob's mother; Theo, Jacob's brother and himself. There were certain rules in their home: 1. Clean up your own mess. 2. Tell only the truth. 3. Brush your teeth twice a day. 4. Don't be late for school. 5. Take care of your brother, because he is only one. But then one day his teacher is found dead, and the police come to question him. And they accuse Jacob of murder... He was just saving his brother.