Every year, the people of the Protectorate leave a baby as an offering to the witch who lives in the forest. But Xan is in fact a good witch who rescues the children. One year, Xan accidentally feeds a baby moonlight instead of starlight, filling the ordinary child with extraordinary magic. Xan decides she must raise this girl, whom she calls Luna, as her own. As Luna's thirteenth birthday approaches, her magic begins to emerge - with dangerous consequences...