Mochizuki enters high school and reunites with his childhood friend and first love, Tsukimi Kawaru. She has transformed from a mischievous tomboy into a refined and beautiful girl, yet she keeps an unnervingly close physical distance that has not changed since their days together. Shortly after the school year begins, a coincidental accident forces Kawaru to reveal her secret: she is a wolf girl, a supernatural being who cannot control her instincts around Mochizuki. Her sister Utsuru arrives to take Kawaru back home for breaking her promise to keep her nature hidden, but Mochizuki objects and devises a plan that allows Kawaru to continue attending high school while keeping her identity concealed. As the two grow closer, Kawaru’s father summons Mochizuki and demands that he break up with her. The reason lies in Mochizuki’s own bloodline: he carries rabbit blood, and when Kawaru inadvertently ingests it, she undergoes a forced and risky wolf transformation. Her father warns that repeated forced wolf transformations carry the risk that she will eventually be unable to return to human form. The narrative follows the couple as they try to navigate the growing danger of their bond while deepening their relationship. Later, a woman claiming to be Mochizuki’s mother appears, telling him that the rabbit must return to the moon. The story builds toward a conclusion that resolves the intertwined conflicts of forbidden attraction, family obligations, and the threat of losing one’s humanity entirely.