Ore no Imouto ga Konna ni Kawaii Wake ga Nai

Ore no Imōto ga Konna ni Kawaii Wake ga Nai (俺の妹がこんなに可愛いわけがない, My Little Sister Can't Be This Cute?), also known as Oreimo for short, is a Japanese light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki. The first volume was published by ASCII Media Works under their Dengeki Bunko imprint in August 2008; as of May 2010, six volumes have been released. A manga adaptation drawn by Sakura Ikeda started serialization in the March 2009 issue of ASCII Media Works' Dengeki G's Magazine. A 13-episode anime adaptation produced by AIC began airing in Japan in October 2010.

Kyōsuke Kōsaka, a normal seventeen-year-old high school student, has not gotten along with his younger sister Kirino in years. For longer than he can remember, Kirino has ignored his comings and goings and looked at him with spurning eyes. It seemed as if the relationship between Kyōsuke and his sister, now fourteen, would continue this way forever. One day however, Kyōsuke finds a DVD case of a magical girl anime entitled Hoshikuzu Witch Meruru (星くず☆うぃっちメルル?, Stardust Witch Meruru) which had fallen in his house's entrance way. To Kyōsuke's surprise, inside the case is a hidden adult video game titled Imōto to Koishiyo! (妹と恋しよっ♪?, Let's Fall in Love with Little Sister!). Kyōsuke attempts to fish out the culprit who dropped the case by bringing up the topic of magical girl anime at the family dinner table. All that comes out is a strong negative reaction from his parents, especially his anti-otaku policeman father.

That night, Kirino bursts into Kyōsuke's room and, in perhaps the first conversation she has initiated with him in years, says they "have things to talk about." Kirino brings Kyōsuke to her room and shows him an extensive collection of moe anime and lolicon bishōjo games she has been collecting in secret.

Ore no Imōto ga Konna ni Kawaii Wake ga Nai began as a light novel series written by Tsukasa Fushimi, with illustrations provided by Hiro Kanzaki. The first volume was published by ASCII Media Works under their Dengeki Bunko imprint on August 10, 2008; as of May 10, 2010, six volumes have been released.

A manga adaptation based on the light novels drawn by Sakura Ikeda began serialization in the March 2009 issue of ASCII Media Works' magazine Dengeki G's Magazine sold on January 30, 2009. The first bound volume was released on ASCII Media Works' Dengeki Comics imprint on October 27, 2009; the second volume followed on August 27, 2010.

Source: Wikipedia