When DI Sebastian Locke gets a call about his ex-wife, Charlie, he fears the worst. Charlie has been a drug addict for years, so Seb has anticipated discovering her death … and wonders how he will tell Tilly, their teenaged daughter. But it’s Charlie’s boyfriend whose body he finds at the squalid flat – and Charlie is nowhere to be found.

But the case soon ramps up as more addicts go missing from the streets. As Seb and the Thamespark squad delve deeper, they uncover the twisted plan behind these disappearances. But can Seb find the shadowy man at the centre of it all – and rescue the mother of his child – before it’s too late?