Yumi, a mother who supports her son who is aiming to enter medical school, works as a nurse. At that time, the director of the hospital tricks her into a sweet trap. Yumi offers her body to the director, who has strong connections, in exchange for his promise to help her pass the exam. The director also makes advances during work hours. She gradually awakens to the pleasures of being a woman that she had forgotten. However, with one letter, those lewd days come to an end, and someone appears before Yumi, who has a void in Kokoro.