Mitra and her younger brother, Babak, are refugees in ancient Persia, living in a labyrinth of caves, scraping by with the food they can steal in the nearby marketplace. Disguised as a boy for safety and mobility, Mitra dreams of returning to her former life of opulence before her father's plot against a despotic king scattered the family. When it is discovered that Babak possesses the ability of prophetic dreaming, he comes to the attention of a local magus, Melchior, who takes the children under his protection as he travels westward, following signs in the stars.