Stranded in the Welsh mountains, seven reality show contestants have no idea what they've signed up for. Each of these strangers has a secret. If another player can guess the truth, they won't just be eliminated - they'll be exposed live on air. The stakes are higher than they'd ever imagined, and they're trapped. The disappearance of a contestant wasn't supposed to be part of the drama. Detective Ffion Morgan has to put aside what she's watched on screen, and find out who these people really are - knowing she can't trust any of them. And when a murderer strikes, Ffion knows every one of her suspects has an alibi - and a secret worth killing for.