A widow named Yuzuri lives with her daughter and grandchild after her husband passed away three years ago. When their daughter gets married and moves in with them, she isn't too keen on sharing their bedroom. Her son-in-law becomes increasingly frustrated by this. As they make love, Yuzuri secretly masturbates while listening to their intimate moments. One day, her son-in-law suggests giving her a massage for her shoulder pain. She agrees to undress for him, revealing her naked body. His hands move from her shoulders down her back and finally onto her ass. He then inserts his finger inside her wet hole, teasingly remarking how easily aroused she seems to be.