During the rare appearance of the once-in-a-century comet Dream Suisei, a strange phenomenon occurs where everyone shares a dream of a distant world. In this shared dream, Melonpanna rescues an egg from peril, only to awaken and discover the egg has mysteriously followed her home. From this egg hatches a kitten named Nyanii, whom Melonpanna nurtures with care. However, their joy is short-lived as they learn that Nyanii is essential to Dream Suisei and must return there to prevent her disappearance. As Melonpanna grapples with the impending farewell, a new threat emerges when Baikinman inadvertently unleashes the malevolent creature Muuma, setting the stage for unforeseen challenges.