On a family trip, the husband finds himself fixated on his stepmother Hisayo Nanami—her composed presence and her alluring, youthful body that defies her age. Ever since the passing of his father-in-law, she has chosen to remain unmarried, living alone, and her quiet strength begins to stir something deep within him. As the journey unfolds, the distance between them steadily closes. Then, in a moment alone while his wife is out, the husband can no longer restrain himself and reaches out to touch her. Their relationship finally takes that irreversible step forward.