When the mysterious boy Frindleswylde enters Cora and Grandma’s house in the woods, he steals the light from their lantern. Without it, Grandma will not be able to return home after work in the dark. Cora is determined to get the lantern back, but first she must follow Frindleswylde down a hole in the pond that leads to his magical frozen kingdom, where he sets her three Impossible Tasks.