After Toshiyo's husband passed away, her daughter and son-in-law noticed her emotional decline and decided to take her out together every weekend to help heal her heart. One day, however, the daughter had to cancel due to work, leaving Toshiyo alone with her son-in-law. Their usual routine suddenly shifted when he said, "You must be tired, Mother-in-law. Let me give you a massage." What followed was an unexpected turn of events. A special day unfolds, filled with warmth and tension, as the relationship between the two takes a deeper, forbidden turn.