In this thrilling conclusion to the award-winning trilogy, Charity and her friends must help Aidan defend the fortress against a militia led by Aidan’s “disenfranchised” human half-siblings who want only one thing: the power of the Klaas. Everything is on the line as Charity must venture into a terrifying world called The Withering to find someone named "Perchta," their last hope for help. But will Charity survive the strange creatures and even more shocking truth that await her?