Two girls go to a party, only one returns alive. Toni, the surviving teenager, is found deliriously wandering the muddy fields of the fens. She has been drugged and it's uncertain whether she'll survive. She says she saw her friend Emily being dragged away from the party. But no one knows who Emily is or even if she's still alive. Meanwhile the drowned body of another girl has been found on an isolated beach. And how does this all relate to the shocking disappearance of a little girl nearly a decade ago, a crime which was never solved? The girl's mother is putting immense pressure on the police to re-open the high-profile case.