The inhabitants of Kaer Moar, living deep under the earth, believe that the Scourge still rages outside their kaer's protective walls-until a youth Named Delain discovers that the keystone responsible for warding off the Horrors is damaged and that the magical device created to signal the Scourge's end hasn't moved in years. Delain vows to save the kaer-but the thing lurking beneath Kaer Moar will not let the people go without a fight.