Dream Suisei, a comet that returns only once every hundred years, passes close to Earth, and while it does, everyone dreams the same dream of a strange, faraway world. In that dream, Melonpanna keeps an egg from being crushed, and when she wakes, she discovers the egg has trailed her all the way home. When a kitten hatches from it, Melonpanna names her Nyanii and begins taking care of her. Soon they learn that Nyanii must go back to Dream Suisei, or else she will vanish. Melonpanna wrestles with the painful farewell ahead, but the bigger trouble begins when Baikinman accidentally wakes the wicked monster Muuma.