3rd grade teacher Aoki Daisuke didn't expect the first class he ever taught to be one of the toughest obstacles of his life. After getting off on the wrong foot with the entire class, a moment of kind-heartedness instantly convinces one of his students, Rin Kokonoe, to make the ill-fated Aoki-sensei her lover. But what exactly are Rin's intentions for wanting to actively seduce Aoki-sensei, and will Aoki-sensei be able to help her to deal with them?

According to Kadokawa, an OVA of R-15 will be bundled with the tenth volume of the novel.

R-15 is about a boy, Taketo Akutagawa, who attends a school for geniuses: Inspiration Academy Private High School. Taketo is a genius novelist and writes erotica. Despite negative perceptions many people have of him, he aims to be at the top of his class and be recognized as the world's greatest writer.

In the midst of a violent invasion of Earth by unknown alien forces, photojournalist Wakatsuki Tetsuya comes across a scantily-clad alien woman, cutting a swath of death through the Terran ranks with her sword. After a chaotic struggle, Tetsuya is knocked unconscious, only to awaken aboard her starship. To his surprise, she turns out to be Kahm, the invaders' princess - and she has picked Tetsuya for a starring role in her upcoming wedding. As the groom...