Please Excuse My Younger Brothers

For high schooler Akiteru Ooboshi, the whole youthful experience thing—like fun, friendships, and even having a girlfriend—is a complete waste of time. So when his best friend’s sister, Iroha Kohinata, keeps teasing him, Akiteru naturally finds it annoying. She practically lives in his room, she’s always on his bed, she’s just a raging storm of clinginess! Why is she only annoying around him?!

Junior High student Nao's brother complex is so strong, it's almost at the point of incest. She's determined to make her brother, High School student Shuusuke, see her as a woman. So determined, that she goes as far as going into his room to throw away all his non-incest related porn. But as she's looking for his porno stash, she finds a photo album... and she's not in any of his childhood pictures. What is going on?

Ah, high school. Is there any better place to start fresh after a horrible middle school relationship? Nope! Not unless your ex ends up at the same school as you and is now your stepsibling. What was supposed to be a sanctuary of peace where I could avoid ever seeing her again has become a living nightmare! Everywhere I look, I see her—in my house, in my school, in my class. There's no escape! She even claims that she’s the older sibling. Like hell she is! But I won't lose to her. After all, I'm the older brother in this new family situation. That’s right, we’re family now. No matter how much we may have thought we loved each other before, we saw one another’s true colors and realized we weren’t meant for each other. That’s why even though we may keep up a buddy-buddy sibling act for the sake of our parents, things will never go back to the way they used to be.

Is insanity hereditary? Shougo Mikadono's beginning to think so, because the terms of his late father's will seem crazy and following them may drive Shougo bonkers as well. Oh, it sounds simple at first: before Shougo can claim his VERY large inheritance, he just has to start attending a certain new school and find a nice girl to marry. It's a little unromantic, but perfectly do-able, right? After all, all the girls seem quite friendly, so all Shougo has to do is find one he has something in common with. EXCEPT, and here's the kicker, it turns out that Shougo has WAY too much in common with one of them, because she's actually his long lost sister! And he has no idea which one she is! Will Shougo meet and court his Miss Right without committing something very morally wrong? Can he find his future bride without slipping into the wrong set of genes? And if his little sister does reveal herself, just how much will be revealed and under what circumstances?