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.

Despite endless research, the human mind remains a mystery to this day. Unknown to the public, there exist special individuals who are able to dive deep into the minds of people and even manipulate their memories. Gifted with this ability, Hiroki, Tsukasa, and Satoru are among those who use their power to commit crime under the orders of their leader, Katsuragi. The three step into the dangerous territory of the human mind in order to destroy their assigned targets while striving to keep their own minds and memories safe. [Written by MAL Rewrite]

After moving into his new apartment, art school student Tatsuhiko Kido discovers a crack in his wall. When he peeks inside, he makes eye contact with his neighbor, Emiru Ikuno, as she masturbates. He rushes next door to clear the misunderstanding and inform her of the crack, but accidentally trips and falls over her in the process. To make matters even worse, Emiru now has photographic evidence that would plainly depict Kido as a sexual offender. Kido then learns that Emiru has a voyeurism fetish, and is blackmailed into leaving the crack as is. Unfortunately for Kido, it doesn't stop here! Emiru is also attending the same art school that he is, and he will be seeing her far more than he would like to. Emiru and Kido are set to embark on a unique friendship with wildly erotic potential.

Nezumi Monogatari is the story of two mice called George and Gerald who embark on a journey together with three friends to find the "Dragon of Light".