Forty-year-old mother Shizuko, worn out both physically and emotionally by her husband's premature death and the daily grind, agrees to a hot spring trip at the invitation of her only son, who lives and works in the city. Seeking temporary relief, she looks forward to relaxation and quality time with her grown son. Sharing drinks late into the night, she begins to step away from her emotionally unfulfilled life—until an unexpected incident that night deeply shakes her. From that moment on, a powerful new emotion stirs within her, directed toward her son, setting the stage for an intense and transformative experience.