Recently, My Sister Is Unusual

OVA bundled with the limited-edition 7th volume of manga. It includes an "exclusive, prohibited" episode that cannot be aired on TV.

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?

Based on the erotic game by NekoNeko Soft. Brother and younger sister-in-law live in the house which parents are often away from. Yuki who is the younger sister is secretly yearning for Kenji who is the elder brother. However, one girl came to show up from the closet in Kenji's room after a certain night. Moreover, her body is transparent, and she looks like the ghost. Her name is Hiyori. She is a friend in their childhood. They are pleased with reunion though Kenji and Yuki are perplexed with the way of Hiyori's strange appearance. However, Yuki gets the mind shaken as Kenji and Hiyori become intimate, and the pain in her mind in the childhood is recalled. At the childhood, Yuki was going to pass the light blue toy ring which Kenji had had to Hiyori in exchange for Hiyori's yoyo. However, because Hiyori became sick, and had moved, the promise was not an accomplishment. Their events in the childhood seem to be related to Hiyori's showing up in front of them. A painful love story of Kenji and two girls progresses.

At the young age of 11, Kotoko Iwanaga was abducted by youkai for two weeks and asked to become their "God of Wisdom," a mediator between the spirit and human worlds, to which the girl quickly agreed but at the cost of her right eye and left leg. Now, six years later, whenever youkai wish for their problems to be solved, they make their way to Kotoko for consultation. Meanwhile, Kurou Sakuragawa, a 22-year-old university student, has just broken up with his girlfriend after he fled alone when the two encountered a kappa. Seeing this as her chance to become closer with him, Kotoko immediately makes her move, hoping to get married to Kurou one day. However, she quickly realizes there is something more to Kurou. With this knowledge, she asks for his help in solving the various issues presented by the supernatural, all the while wishing her newfound partner will eventually reciprocate her feelings.