Nanami, a busty wife living in a housing complex, suspected her husband, a salaryman who frequently exchanged emails with someone, of cheating. One day, Nanami witnessed her husband walking with a young woman. Consumed by anger and frustration, she began to masturbate wildly, only to lock eyes with a middle-aged neighbor through the open window. The man, who meant no harm, knelt in apology. These two who should never have crossed paths began an intense affair that left them drenched in sweat, all starting from this voyeuristic incident.