translated from wikipedia:

Protagonist Kobayashi Kouji is transfering to Aoba High School, where his older brother was recently hired as a teacher. The school has a long history of being a prestigious girls high school, and only a few years have passed since it became co-ed. As a result, there are few boys, and the girls remain in charge inside the school. In order to combat the female dominance at school, Kouji forms a kendo club with some of the other male students. In the class into which Kouji transfered, he finds the high-acheiving Yoshikawa Misao, who happens to live in the apartment next to Kouji's--so close that they could talk to each other from their windows. While Kouji and his kendo club are in competition with Misao and her baton club, they slowly start to come to a mutual understanding.