While exploring an ancient storeroom of the Great Gummies, Tummi discovers a mechanical decoy used to make dragon footprints, but accidentally starts the machine and begins bouncing all across the land. The footprints attract a real dragon. The knights of Dunwyn also see the machine and think it is a real dragon. Zummi gives Cubbi a whistle from his old treasure chest while Sunni is having trouble babysitting Cubbi. The whistle attracts a brine dragon, which takes Sunni and Cubbi on an unexpected adventure.