Long, long ago. To protect this newly born land, the gods of the Land of the Rising Sun held a festival to select twelve divine messengers. The Eto Girls chosen as the zodiac signs have protected this land for ages. Alongside the cat who was not chosen. This is a tale of the cat and the twelve Eto Girls, passed down since ancient times... Several months have passed since the once-every-sixty-years Zodiac God Selection Festival, "ETM12," concluded, and the millennia-long feud between the cat and the rat (sort of) reached a resolution. "Nya~tan," having returned from her Solar Battle pilgrimage around the world, takes advantage of Takeru being away on a school trip to indulge in her usual carefree, boisterous fun with the Eto Gods. Then one day, a mysterious Eto Girl, "Naa~tan," appears. The Eto Gods are somewhat perplexed by the arrival of "Naa~tan," who adores Nya~tan like an older sister and makes no attempt to hide her straightforward affection. Nya~tan, flushed with excitement and overjoyed, hits it off perfectly with Naa~tan. Before they know it, everyone welcomes this new housemate, and they await Takeru's return with their usual lively clamor. One day at the Takeru residence, the Eto Gods sense an unusual shift in the world's movements due to a trivial incident. Suddenly, Chuu-tan appears from the sky. With an unusually grave demeanor, she opens her mouth and delivers "a certain message." "The seal is about to break..." In truth, "Naa~tan" is a divine messenger entrusted with a "mission" that even she herself has forgotten...