High school student Hiroki is a perfectly average guy, except for one thing: his insatiable fetish for glasses. Due to this fixation, Hiroki rarely goes a day without engaging in sexual activities with his girlfriend, the gorgeous, glasses-clad Hitomi Kurumizawa, in his home. One day, however, he is caught in the act by his older sister, Natsume—a bespectacled beauty—who decides to "punish" him for the noise caused by his escapades. [Written by MAL Rewrite]