When the dismembered body of a headmaster is found on the derelict site of a former school in Sheffield, DI Diana Walker finds herself chasing shadows. Faced with missing teachers, unreported crimes and silent witnesses, Diana is running out of leads. Her colleagues insist this is just another instance of gang violence, but Diana knows there's something more. Something everyone's too scared to talk about. With her reputation on the line, Diana is determined to find the truth. Her search for answers leads to Sheffield's neglected underbelly, where she finds distrust, horrifying secrets and a whole new understanding of justice.