Ore no imouto ga konna ni kawaii wake ga nai

Kyosuke Kosaka, a 17-year-old high school student from Chiba, has had an unsatisfactory relationship with his younger sister Kirino over the years. For as long as he can remember, Kirino has ignored him and looked at him disdainfully whenever they were together. It seemed like their sibling bond would never improve. One day, Kyosuke discovers a DVD case in their home entrance way which contains a magical girl anime series. To his surprise, inside the box is an erotic manga (eroge). This discovery shocks Kyosuke and leads him to learn that both the DVD and game are actually Kirino's collection of moe-themed anime and younger sister-related eroge. That same night, Kirino invites Kyosuke over to her room where she reveals herself as a passionate otaku who has been collecting such material in secret. Kyosuke quickly becomes close with his sister and starts helping her explore her hidden hobbies. The series then follows Kyosuke's journey as he tries to mend their broken relationship while also coming to terms with Kirino's true feelings for him. They learn how to reconcile their personal lives with their shared interests, restoring the bond between them.