After a long and tiresome cat-and-mouse game, tranquility reigns among all. Suddenly, an Eto-musume dubbed Na-tan emerges, intriguing the 12 signs and bringing immense joy to Nya-tan with her simplicity and purity. Simultaneously, Chu-tan emerges with a dire prophecy of a catastrophe on the horizon. The cryptic message 'The seal... has been broken' hangs ominously. As questions swirl, who is this enigmatic Na-tan from the Zodiac, and what ancient deity stirs beneath the shattered seal?