Note: Kyousuke has magic that lets him look Boss at all times.
It's a story about an older brother named Kyousuke who is enstranged from his sister. He aspires to be normal. His sister, Kirino, is a star athlete, talented genius, and a model, and beyond all of that the case could be made that she despises his very existence. For a long time Kyousuke was okay with this, but then he discovered Kirino's secret hobby; imouto-con eroge, otherwise known as hentai games focused on, you guessed it, little sisters and older brothers.
Being a manly man, he doesn't get on her case about her interests, and soon he's helping her dive headfirst into the otaku culture. Unfortunately, she drags him along for the ride. Over time they grow closer to eachother, and when her hobby is in trouble of interfering with her normal life he's always taken the blame.
So, this is the story of two enstranged siblings slowly connecting to eachother, one learning how to emphasize with others and how to be a good person, the other learning that normality isn't all that great and that some things take precedence over his own life.
And... then you get to the main problem(for the fandom, at least). It's a series about an older brother connecting with his little sister because she plays hentai games focused on older brother/little sister pairs. The pairing is so ogddamn obvious that a person could see it a fucking mile away. Of course, there are many who argue that it's simply siblings getting connecting and growing to love and support eachother as family. But still. There's at least as many, probably more, who argue that it's basically inevitable for one or the other to realize that they love eachother in the romantic sense. I'm of the latter viewpoint, and thus reccomend the following story: The Sibling Complication, by Eliya Shirwood, on Fanfiction.net.