Kaoru and Yuji are childhood friends and best friends. They are close enough to say anything to each other that Yuji doesn't think they have any romantic feelings for each other. One day, Yuji decides to stay over at Kaoru's house. Kaoru's clothes accidentally slip off and Yuji spots her nipples. "Huh... Was she always this sexy...?" Since then, Yuji has been strangely conscious of Kaoru, who he thought was his best friend. And for some reason, Kaoru's behavior has been different than usual...