After losing her husband, Chiyoko lives peacefully with her daughter and son-in-law, maintaining a good relationship with her son-in-law. However, despite her age, she remains sexually active, and the loneliness of widowhood becomes an unbearable burden. She channels her passion into daily masturbation, growing increasingly intense and reckless. Desperate for affection and determined to hide her actions from her son-in-law, she becomes consumed by self-pleasure—until one day, her longing drives her into an illicit affair with him.