Yugo, an adventurous and brave young girl, runs away from home after being scolded by her father. She returns to the fantastical kingdom in the clouds to find her friends Lala and Uncle Bear. Just as they're celebrating their reunion, a crisis breaks out: all living creatures in the kingdom are shrinking! With the help of Potato's son, Mili, Yugo, Lala and Uncle Bear realise that the crisis can be resolved if they can only find the water's source.
