Yuuki first met Kotonoha at the school library in the beginning of second semester, but there was no progress with their relationship. They just frequently came to the school library... One day, he sees Roka at the school library and he meets her again through his older sister, Chie, on the same night. Yuuki gradually falls in love with Roka. Roka is also attracted to Yuuki. Their love, however, doesn't go smoothly...
Yuuki hears a rumor that Roka is in love with Makoto. Later he hears that Makoto is close to another girl... Yuuki decides to ask Kotonoha, Makoto's girlfriend, about it to make it clear the fact. From that day, Yuuki's eventful school life starts...
