Naho, an eleven-year-old girl, lives with her father and her two-year-old brother Jun. Her mother died after giving birth to Jun, so Naho has to take care of young Jun at home. Understandingly, this situation is frustrating to little Naho. A girl of her age would be dying to go out and play with friends, but because of Jun, she has to give priority to her duties. 
One day, a bizarre man, wearing a long coat and with a big suitcase in his hand, turns up in front of Naho. He introduces himself as "Kotaro the Dreamball Dealer" and tells Naho he can take her to a dreamland away from her everyday life. But after this encounter, strange phenomena begin to happen to Naho. 
Now Naho is having fun with her friends, and several different worlds come and go before her eyes. Then she finds herself with his father and mother, only the three of them again... But as she starts feeling anxious, the next moment she finds herself wandering into Jun's dream! 
Naho is confused. What would she ask to Kotaro? What does she really desire from the deep of her heart? 
(Source: Production I.G.)