Ryouko planned to wear her favorite skirt to a class reunion, but it no longer fit. Shocked by this, she became determined to lose weight. Using a balance ball for exercise, she began sweating gently, her skin flushing from the effort. Watching his mother in this state, her son Tetsuya found himself overwhelmed with frustration and lustful thoughts. This moment revealed more than just the physical effects of exercise—it exposed the fragile, underlying tensions within their family relationship.