Merlin's Nightmare (The Merlin Spiral #3)

Arthur, now eighteen, is missing, and Merlin must find him before a shadowy pursuer catches him first.
With the High King and his kingdom caught in a trap of sinister deceit, Merlin has to find a way out before all is lost. Having everything to fight for, and almost nothing to fight with, Merlin and Arthur must rally Britain’s warriors against three overwhelming enemies: Saxen hordes in the south, Picti raiders in the north, and a chilling new enemy that has arisen in the west. At the same time, Morgana brings Merlin’s deepest fear to life and sets a horde of werewolves loose to destroy Britain. But when the secret purpose of this nightmare is finally revealed, will Merlin and Arthur find a way to survive—without unleashing an even greater evil?