Michika, her son, and her husband are going to a concert by the popular idol group "Puri Puri Princess Z" this year. - The night before, Michika was dancing to a popular Puri Puri Princess Z song with her son, looking forward to the concert, when she received a phone call. - The caller was Kenichi, a younger sex friend I met at my part-time job. - Then, on the day of the concert, Michika pretends to be sick, breaks her promise to her son and husband, and brings Kenichi into her empty house...