The Warrior King (The Dark Citadel #4)

Marching at the head of a vast army, the young ruler of the Free Kingdoms lays siege to the Dark Citadel, hoping to throw down the Dark Wizard before he can recover from the crushing defeat of the previous summer.

But the Dark Wizard's weakness was only a feint, and he emerges from his citadel at the head of an unstoppable force of undead knights. With this horrifying new army at their front and an old traitor raising trouble to their rear, the armies of the Free Kingdoms and their king will face their deadliest threat.

Book #4 of the epic fantasy series, The Dark Citadel, by Wall Street Journal and USA Today Bestselling Author, Michael Wallace.