A 15-year-old schoolboy is accused of the murder of one of his teachers. His lawyers, the guarded veteran, Judith, and the energetic young solicitor, Constance, begin a desperate pursuit of the truth, revealing uncomfortable secrets about the teacher and the school. But Judith has her own secrets which she risks exposing when it is announced that a new lie-detecting device, nicknamed Pinocchio, will be used during the trial. And is the accused, a troubled boy who loves challenges, trying to help them or not?