After so much danger, Nessa and Anto can finally dream of a happy life. But the terrible attack on their school has created a witch-hunt for traitors -- boys and girls who survived the Call only by making deals with the enemy. To the authorities, Nessa's guilt is obvious. Her punishment is to be sent back to the nightmare of the Grey Land for the rest of her life. The Sidhe are waiting, and they have a very special fate planned for her.

Meanwhile, with the help of a real traitor, the enemy come pouring into Ireland at the head of a terrifying army. Every human they capture becomes a weapon. Anto and the last students of his old school must find a way to strike a blow at the invaders before they lose their lives, or even worse, their minds. But with every moment Anto is confronted with more evidence of Nessa's guilt.

For Nessa, the thought of seeing Anto again is the only thing keeping her alive. But if she escapes, and if she can find him, surely he is duty-bound to kill her...