A young girl and an old man, through caregiving, become aware of each other as men and women and develop a physical relationship. A female college student who volunteers for caregiving for future work and social service becomes responsible for an elderly man who lives alone, often sick, and has lost his wife. The old man, who thought of the devoted and kind girl as a granddaughter, could not suppress his sexual desire for the girl's plump cleavage, despite his vitality in the lower body, and masturbated with his apron while his genitals protruded from his diaper. However, the girl, who accidentally saw the act, was nervous about the old man's erection. She believed that taking care of the lower body was also part of caregiving and served him. From then on, like a kite whose string had been cut, the two crossed the line.
