This is the third in Pierce's new fantasy quartet, which began with Sandry's Book. Four young friends are blessed and cursed with specific magical skills, which they must learn to manage for the betterment of their world. Daja has a way with fire. She uses this gift as a blacksmith, and at the story's start she finds herself mysteriously making a plant of living iron. How this creation helps Daja to overcome the blight of her young life -- being an outcast from her trader clan -- is the grist of the tale.