Hinatsu Hoshikawa has a reputation at work as a "capable boss," "talented designer," "cool beauty" and "mature woman." This perfect-seeming office worker has two secrets: at home, she's a lazy goof, the complete opposite of her work persona... And she lives alone with a high school student, Touya Isshiki! Though they're not related by blood, Hinatsu sees Touya as an irreplaceable part of her family. One night, however, this young man pours his heart out and reveals his deep, mature love for the older woman... "I've waited so long for this day... When I become an adult."