Niina married an older husband who had a young NEET son. While her married life seemed stable on the surface, Niina gradually began feeling stressed about her husband's unsatisfying performance in bed. One day, while visiting a social welfare center for her stepson, she was forced by a man to receive a shoulder massage—and to her surprise, she felt pleasure from it. By chance, her stepson, who had secretly harbored feelings for her, witnessed the incident, setting in motion a new and forbidden relationship.