Ore no Imouto ga Konna ni Kawaii Wake ga Nai

For several years, Kyousuke's relationship with his younger sister Kirino has been cold, to the point that they only share greetings. But one day, Kyousuke finds a moe anime DVD fallen in their entry hall. His interest piqued, he looks for the owner, only to realize it belongs to Kirino. He's shocked, but more surprises lie just ahead...