From the outside, the cathedral town of Lafferton seems idyllic, but in many ways it is just like any other place. It suffers from the same kinds of crime, is subject to the same pressures from a rapidly changing world, has the same hopes and fears as any number of towns up and down the land.When one day DC Simon Serrailler is called in by Lafferton's new Chief Constable, Kieran Bright, he is met by two plainclothes officers. He is asked to take the principal role in a difficult, potentially dangerous undercover operation and must leave town immediately, without telling anyone -- not even his girlfriend Rachel, who has only just moved in with him. Meanwhile, Simon's sister Cat is facing difficult choices at work, as Lafferton's hospice closes its bedded units; and at home, as her daughter is presented with a glittering opportunity that they would struggle afford. And all is not well with Simon and Cat's step-mother, Judith, either. To complete his special op, Simon must inhabit the mind of the worst kind of criminal. This takes its toll on Simon and, as the op unfolds, also on the town and some of its most respected citizens.