Kyouko Irisu is a university student. Her story revolves around her childhood and a boy named Uujima Satoru. When she was in elementary, Irisu was frequently without friends, so she gravitated to U-Tarou, the school rabbit, and took care of it. The rabbit died one day, with Irisu finding its head being licked by the school cat, causing her to foster a hatred towards cats. Years later, she develops an infatuation with Uuji after viewing his notebook, which contained suicidal cat drawings.