Kekkon × Renai.

Shiho is an unfortunate woman; her marriage only lasted for three days because of the death of her husband. She then decided to be the guardian of her late husband's little brother, Makoto, who was still in elementary school. Nine years later, it turned out Makoto is actually the one who's been taking care of Shiho. On his eighteenth birthday, Makoto asks Shiho (age twenty-nine) to take responsibility and marry him.