Rena has raised Tatsuki as a single mother. Although her partner initially pressured her to have an abortion, Rena chose to continue the pregnancy on her own terms. Since then, she has had no contact with him. Determined to provide a good life despite being a single parent, Rena has worked hard as a career woman. Tatsuki, understanding their situation, has always been considerate, never making demands and putting his mother's feelings first. Yet, deep down, he has always felt loneliness. When Tatsuki entered university, Rena used up her accumulated paid leave, and the two went on a trip together. However, her mind remained preoccupied with work, leaving her unable to fully enjoy this precious family time.