Mahiro gave birth to Taiichi, but Taiichi's father had an affair with Mahiro. Mahiro chose the path of being a single mother and raised Taiichi. To not make him feel pitiful, she worked desperately, and Taiichi responded by not being demanding and helping with household chores. However, loneliness accumulated. Meanwhile, around the time Taiichi was about to graduate from university, Mahiro took a late summer vacation with Taiichi to use up her accumulated paid leave.
