‘You can’t upset anyone looking into old bones.’

DCI Bill Slider’s out of favour in the force – for accusing a senior Met officer of covering up an underage sex ring. As a punishment, he’s given a cold case to keep him busy: some old bones to rake through, found buried in a back garden, from a murder that happened two decades ago, and with most of the principal players already dead.

Surely Bill Slider can’t unearth anything new or shocking with these tired old bones?