A priest is dead. Picking through the rubble of the demolished Edinburgh tenement, Detective Inspector Adam Ferguson discovers that the explosion wasn't an accident. When a bishop is assassinated soon afterwards, it becomes clear that a targeted campaign of killings is underway.

No one has seen anything like this since the Faith Wars. In this enlightened age there's no religious persecution, but believers are a marginal and mistrusted minority. And now someone is killing them. But who? And - perhaps more importantly - why?

The more his team learns, the more the suspicion grows that they may have stumbled upon a conspiracy way outside their remit. Nobody believes them, but if Ferguson and his people fail, there will be many more killings - and disaster on a literally biblical scale . . .