From today, Meguru Kinosaki is a freshman in high school. But it's not only that she hasn't had a first love yet; she's in fact a clean girl who's never been in contact with any guy apart from her older brother Toshiya. With this pure Meguru, her classmate Yuuma falls in love at first sight. He starts a determined attack, but the over-protective big brother blocks his way! Now Meguru's days start to turn around between a big brother with a sister complex and a pushy boy…!?