When sixteen-year-old Ella Andrews's best friend, Avery, goes missing, she'll do anything to get him back-starting with punching the no-brain cop who couldn't care less about the disappearance. Ella's convinced Avery's been kidnapped, and she tries everything to find him-even fol-lowing a strange shadow to another world where the constellations are real-life figures in the sky. But three star groups have fallen and are destroying the world. The fallen constellations are not the only enemy. Melanie, the princess of Stellaris, is forcing Ella, Avery, and an army of other kids kidnapped from their world to fight the rogue con-stellations, even as the land is draining away their life. The longer they stay, the more they fade into substanceless shadows-a fate worse than death. Can Ella save Stellaris before there's nothing left of her and Avery?