A serial killer who is burning the bodies of his victims to a crisp is operating in Ellendon. Meanwhile, Enwright introduces junior DC Martin Simmons to the team, much to the dismay of Creegan, who takes an instant dislike to him. As another victim of the killer turns up, Creegan realises that all of the murders are linked to a psychiatric hospital which burnt to the ground in 1989.

Creegan and Taylor come closer to identifying the killer when a fourth victim, headteacher Claire Logan, is found dead. They soon realise that victim Debbie Lewis' best friend, Lyn Sotherby, is none other than Susan Etchells in disguise, and they soon track her down to a disused hospital in Lincolnshire, where she has another victim ready and waiting. Creegan then puts himself on the line to secure the safety of the hostage, much to Taylor's dismay.