Years and years ago now I watched the anime OniiAi. At the very end of the series it is reveled that Akito and Akiko are not twins at all. They are step siblings and for some reason Akito will not tell his step-sister that. After that I blundered in one that shall remain nameless. It had a very similar plot of a guy keeping the secret that he was not related to his sister. I gave up on that series because it became a total train wreck after only a few episodes. (By the way, the manga was released her in America, but not the anime.) After that was another series about a boy and twins.
"What the hell is with anime and step incest all of the sudden?" I asked myself. I went to Google and typed in "What the hell is with anime and step incest all of the sudden?" This image popped up.
I was prepared to hit the big red x button at the top of the window when I noticed in one of the search results was that Yui Horie was the voice actress for this character. So I clicked the link to a YouTube video and found myself laughing at what I saw. I gave the first few episodes a chance and I was hooked. Yuru Yuri is a silly light hearted look at the yuri genre of anime. It's become so popular that it is a world wide phenomenon.