When a seventeen-year-old girl vanishes from her home overnight, DI Laura Hart knows that time is of the essence.

Then, an inmate at the local prison is murdered in her cell and suddenly Beaumaris CID is juggling two major investigations.

With inmates refusing to talk to the police, Laura is forced to take drastic action: going undercover behind bars.

With everyone under suspicion, Laura’s true identity must be kept a secret, meaning no one can protect her.

Locked in with a killer, it’s a race against time – can Laura find a lead… before she’s found out?