This spellbinding fantasy weaves the tantalizing tale of a young woman's struggle against her supernatural twin. But when the mystical island of Clouds End comes under attack by the invading forces of a mad emperor, the pair must forge an uneasy alliance to defend their home. "Stewart's beautifully lucid, poetic prose makes for a narrative of commanding power and enchantment that echoes the best of Le Guin and Tolkein." - Booklist.