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, while dancing to a popular song by Puri Puri Princess Z with her son, Michika gets a phone call. The caller is Kenichi, a younger sex friend she met at her 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...