Gr 4–6—In this conclusion of the trilogy that began with Winterling (2012) and continued in Summerkin (2013, both HarperCollins), a poisonous curse called the stilth is oozing through the magical realms, spreading stillness and rot wherever it goes. It stems from the fact that young Fer, part-human Lady of the Summerlands, asked that all Lords and Ladies swear an oath to remove their glamories. The Forsworn have defiantly kept this masking magic, which not only makes them beautiful but also causes them to resist change and desire power. Meanwhile, Rook, Fer's tricky friend, and the Puck brothers have found a powerful and dangerous antidote to the glamorie in the form of a giant spider's web. What Rook does with this antidote causes the fragile trust between him and Fer to finally snap. After the Forsworn spirit Fer away to a remote, magical island, only Rook can rescue her-and only Rook and Fer together can save the realms, not to mention Fer's human grandmother. Fer's fierce determination to deal with the consequences of her actions meshes with Rook's realization that Fer is every bit as important to him as his brothers. This creates a tension that keeps the pages turning, even as the stilth threatens to destroy the world. Fer's refreshing humanity and Rook's exasperating but charming trickiness add humor and warmth to this fine fantasy.—Eva Mitnick, Los Angeles Public Library