Mary and her husband have been married for a long time. Due to the significant age gap between them, the husband's health is not good. Mary is at the peak of her sexual desire, but her husband is no longer interested, and they haven't been intimate for a long time. Today, Takuya, the husband's grandson, visited them while on a business trip. It has been a while since they last met, and Takuya still finds Mary attractive. Since they didn't book a hotel, Mary's husband suggests Takuya stay at their house. The next day, Takuya accidentally sees Mary changing clothes, which arouses his desire. When Mary leaves the house, he sneaks into her room and masturbates using the panties she just changed out of! While he is in the act, Mary suddenly returns, and Takuya quickly steals the panties and takes them to his room. Mary discovers the missing panties and figures out what just happened. Surprisingly, she is not angry at him; instead, she has found a partner to help release the sexual desire she has been suppressing for many years...