After losing her husband, Sumire began living with her daughter and son-in-law. Though memories of her late husband linger in her heart, she gradually adjusts to her new life. However, one issue begins to trouble her deeply—the nightly intimacy between her daughter and son-in-law. While the couple shares a strong relationship, the sounds of her daughter's pleasure each night stir discomfort within Sumire. The truth is, she finds herself increasingly drawn to her son-in-law's virile physique. One day, noticing her daughter has gone out, Sumire peeks into her son-in-law's room—only to find him in the middle of masturbating. Flustered, she quickly enters, trying to calm him with a gentle voice. Softly apologizing for interrupting, she reaches out her hand toward his aroused member. That single moment sparks a profound change within her heart.