One year Xan accidentally feeds a baby moonlight instead of starlight, filling an ordinary child with extraordinary magic. Xan decides she must raise this girl—whom she calls Luna—as her own. But as Luna's 13th birthday approaches, her magic begins to emerge—with dangerous consequences. Meanwhile, a young man from the protectorate is determined to free his people by killing the witch. Deadly birds with uncertain intentions flock nearby. A volcano, quiet for centuries, rumbles just beneath the earth's surface. And the woman with the tiger's heart is on the prowl.

Highly acclaimed author Kelly Barnhill has written an epic coming-of-age fairy tale destined to be a modern classic.