Michika, her son and her husband are going to a concert of the popular idol group Puri Puri Princess Z this year. - The night before, while looking forward to her concert and dancing a popular song of Puri Puri Princess Z with her son, Michika receives a phone call. - The owner of the phone was her younger sex friend, Kenichi, whom I met at a part-time job. - And on the day of the concert, Michika used a false illness to break the promise between her son and her husband and brought Kenichi to her home where no one was there.