The death sentence has returned to the UK. The cost of housing killers during their life time has become far too costly for the government. Only one place was willing to house the final prison the murderers will ever attend. Callington Island is what many would consider the ideal place to settle down for a quiet life. Away from the hustle and bustle of modern city life. A place where everyone knows everyone. That was, until Sister Trinity is found murdered. Everyone naturally assumes this must be the work of an escaped prisoner as no islander would surely be capable of such a heinous crime. Father Matthew, the island's priest and every islander's go-to in times of need, decides to give Nigel, the likeable but inept island bobby, a helping hand to solve the case. As the mystery unravels, there is a dawning realisation that this island, and its inhabitants, aren't quite what they seem.