Adolescence is the story of a 13-year-old boy, Jamie Miller, who is arrested for the murder of a girl called Katie Leonard at his school. Throughout the harrowing first episode, the boy is distraught and denying any involvement in the crime as Ashley Walters’ DI Bascombe arrests him in his bedroom and takes him – in the series’ famed one-shot style – to the local police station to be assessed and interviewed.