Dealing with the world's most annoying childhood friend, Miyauchi Misao, is Kudou Yuusuke's daily struggle. She constantly clings onto him - waking him up every morning, following him around, and now, even more awkwardly, because of her newly acquired womanly figure. They are presumed to be a couple in high school, which ruins Yuusuke's chances with other girls.
Unexpectedly, Misao announces her engagement; she is getting married in the spring but still hangs around Yuusuke like usual. The news triggers unfamiliar feelings of jealousy in Yuusuke, and he decides to take action. He sets a goal to become popular and find a girlfriend before Misao ties the knot.
