The Kurbs give people light and warmth to establish a city, on one condition: The people must return the Power every year or risk losing the city--forever. This system works for centuries until evil Mr. Underton tries to steal the Power. If he succeeds, the Kurbs will take back the City, reducing it to a dark and frozen tundra. It's up to Carlos and Sarah to find the Power--housed in a subway token--and keep the City safe, despite secrets of Sarah's history that are entwined with the token.

Originally published: [New York] : Orchard Books, 1993.