Kanenone Academy was an all-boys high school isolated from the world by mountains and hills. Yusuke Takasaki, the average 11th grader, led a normal life in the academy until the academy announced attempting for co-ed, and high-school girls were being transferred for the summer semester.
Outraged over a prank pulled on her by the Baka Trio, Futaba decides to leave Kanenone for home. In her search for a short cut to the bus stop, she gets lost in the surrounding forest and injures her ankle.
Futaba realizes she is starting to develop feelings for Yuusuke. Midori notices this and confronts Yuusuke about Futaba. That evening, the Baka Trio (and a reluctant Yuusuke) attempt to break into the girls' dormitory while the girls are asleep.
Alone in the outdoor bath, Reika delivers a surveillance report on Midori and her attempts to attract the interest of Yuusuke. Soon after "signing off", she is joined by Chigusa and the rest of the girls.
Chigusa organizes a late-night "test of courage", with the boys and girls pairing off. To Midori's dismay, Yuusuke draws Futaba as his partner. Reika sees this as an opportunity to bring Yuusuke and Futaba closer.
After a failed examination, Chigusa assigns Yuusuke to tutor Midori in the hope of bringing her grades up. As an incentive, she tells Midori that Yuusuke will give her a reward if her test results are above average.