Six months ago, Chigusa began living with her daughter and son-in-law after her daughter's marriage. Widowed and estranged for years, one day she accidentally witnessed the couple having sex, which sparked intense arousal she hadn't felt in a long time, leading her to masturbate. Since then, Chigusa started secretly watching the couple's intimate moments. In the kitchen, in the bathroom—each encounter reignites her desire, and she repeatedly pleases herself. One day, while her son-in-law is in the kitchen, Chigusa enters wrapped only in a towel, which slips and falls, leaving her completely naked. Overcome with excitement, he pins her down, whispering, "I could hear you masturbating in the bathroom," as he moves closer, giving in to temptation.