Forty-year-old Hatoko currently works in the planning and development department of a cosmetics company, where she serves as a section chief assistant. Living alone, she spends each lonely night drinking a glass of watered-down liquor before drunkenly lying in bed, reminiscing about the "Best Ten" moments of her past life. Memories such as her grandmother's passing, running away from home, her first overseas trip, getting into university, her first relationship with a boy, and breaking up with a boyfriend all stir her imagination, yet leave her with a lingering sense of melancholy. Despite graduating from the prestigious University of Tokyo, she feels increasingly distant from the ideal life she envisioned during her high school days. Just then, she receives an invitation to a class reunion, and the name of her first love makes her heart flutter...