When their parents disappear in the middle of the night, a cryptic picture message from their mother leads young sisters Summer and Bird through a familiar gate and into the woods, where the sad, electric song of a tiny patchwork bird draws them Down. In this ruined, frozen world of birds, their divided hearts will lead them in very different directions in a quest toward untied goals- vanquish the ravenous, bird-swallowing Puppeteer; help the birds find their way back to their true home; and reveal the true heir to the swan queen's throne. But when the border of the birds' home is finally in sight, the world of Down will turn on itself, demanding a sacrifice and threatening the fate of all who live there. With breathtaking language and deliciously inventive details, Katherine Catmull has created a world unlike any other, skillfully blurring the lines between magic and reality and bringing to life a completely authentic cast of characters and creatures.