Even now, Yumiko has a good relationship with her husband. They still have sex. However, recently her husband's frequency has decreased, leaving her sexually frustrated. To alleviate this, Yumiko starts exercising using an exercise ball given to her by her son. One week later, Yumiko sprains her foot during the exercise. Her son rushes over and stretches her leg to help it heal. As he touches her sweaty body, her son becomes aroused. Yumiko also begins to feel strange from being touched by her son. Though they both try to act calm, they start becoming aware of each other…
