In a shocking incident that sent waves of disbelief across the United Kingdom, a 15-year-old student named William Cornick brutally murdered his Spanish teacher, Ann Maguire, in the middle of a classroom lesson. The case, which was the first of its kind in the country, left the school and the local community devastated, as they struggled to understand how a seemingly model pupil could commit such a heinous act. With exceptional access to real police tapes and interviews with those closest to the victim and the perpetrator, the investigation reveals the chilling details of the crime and the disturbing motivations behind it.