With Fairloch safe from the villains who sought to wrest power from the royal family, the resources of the city are diverted to a last-ditch effort to find a way to stop their implacable foe. Slow progress toward a solution is being made, until the immortal engine of destruction prematurely breaks free of its century-old prison and embarks upon a single-minded quest for domination of the land.
With the countryside awash with deserters and brigands fleeing the onslaught, Aiden Wainwright and his companions must face down old enemies and forge new alliances to aid the beleaguered country in the impending clash against their relentless enemy. But before they confront it, Aiden must learn the answer to a question of singular importance: How do you kill that which cannot be killed?