Tsutomu usually masturbates and shows no interest in anything else. Chisato couldn't help but worry about her son. One day, Tsutomu came home from school with an injury, and when I asked him why, he said, "I got 0 on a test, and I was laughed at, so when I got angry, we got into a fight." Worried about his son's future, Chisato decides to use her own body to teach Tsutomu to study so that Tsutomu will not suffer any more.
