Antisocial behaviour is on the rise on the streets of Liverpool. Swift and silent, a sinister gang is patrolling the city on electric motorbikes, scouting for opportunities to steal. DI April Decent and her trusted team of detectives are facing a complex series of crimes including the cold case of a young woman who died almost a year earlier. The perpetrator remains in the shadows, a traumatised past leaving them hell-bent on atonement, hoping to find a way to cleanse their soul of guilt. 'The Controller' of the gang pulls their strings, their orders becoming ever more ambitious and demanding, until a robbery goes wrong, and a gang member is arrested.