A tiny chipmunk named Oskar accidentally stows away on an enormous Great Lakes freighter. Can he survive an epic trip—and find his way back home?

Near a bustling harbor, a plucky chipmunk's love of tomatoes earns him a heart-pounding ride "up up up" onto a huge ship. After iron ore pellets thunder into the cargo holds, the boat sets sail across Lake Superior—with Oskar still aboard! Lost and desperate to return to land, Oskar explores the enormous boat for a way out. The metal, the machines, the noise—it's all so different from his small home in the oak tree. Tasty treats in the galley calm his nerves, but when he ventures up to the pilothouse, where sailors steer the ship, he's shocked to see his bridge and his oak tree fading into the distance. Soon, the lake stretches endlessly in all directions.

As he searches for a way home, Oskar discovers excitement—and danger—instead. He's never before seen a dizzying drop to icy water; an avalanche of mail; a roaring, rumbling engine room; or a steel boom swinging through the sky to deliver a ship's cargo. Though he encounters amazing wonders on board, he can't find the one thing he needs most—his oak tree back at the harbor. Will Oskar ever make it home?