Shiho gave birth to Yuki when she was 20 years old. As Yuki grew up, she and her husband became sexless, but Shiho's sexual desire increased. However, one day her husband's infidelity was discovered, and their relationship quickly cooled. After Yuki entered university, the divorce talks progressed, and all that was left was to submit the paperwork. When summer vacation came and Yuki returned home, Shiho decided to report to her son at the station before submitting the paperwork.
