Spirited, restless Gracie Lockwood has lived in Cliffden, Maine, her whole life. She's a typical girl in an atypical world: one where sasquatches helped to win the Civil War, where dragons glide over Route 1 on their way south for the winter where giants hide in caves near LA and mermaids hunt along the beaches, and where Dark Clouds come for people when they die.
To Gracie it's all pretty ho-hum...until a Cloud comes looking for her little brother Sam, turning her small-town life upside down. Determined to protect Sam against all odds, her parents pack the family into a used Winnebago and set out on an epic search for a safe place that most people say doesn't exist: The Extraordinary World. It's rumoured to lie at the ends of the earth, and no one has ever made it there and lived to tell the tale. To reach it, the Lockwoods will have to learn to believe in each other and to trust that the world holds more possibilities than they've ever imagined.