Yup, I did have that one in mind. I binged a bunch of bad animes recently and that was one them. Along with Mayoi Neko Overrun, "I Don't Like You at All, Big Brother!!" and "My Sister is Among them". Out of these and that "sister is unusual" one, "My Sister is Among Them" is actually by far the best show. And for that one, the synopsis is that a rich heir has to find a wife at an elite school, but one of them might be his sister, so he's worried he might accidentally bang his sister. And ... it's still the best show of these four by far, which probably says more about the other shows than that one.
I started watching Ranpo Kitan - Game of Laplace and it's a weird experience. It's one of those "wrongly arrested as a serial killer" kind of things except in this one I couldn't care one bit if the hero gets stitched up for the murders. He's an emotionless creep who hasn't batted an eyelid at the "Ed Gein's house of horrors" type of stuff. He's the sort of guy who'd calmly go "oh look, he made your mother's head into a lamp. how interesting". And when he got arrested he just thought that was interesting too, rather than freaking out, since he likes mysteries and "games". I'm not sure if the character is meant to be a complete sociopath or if it's just bad writing / voice acting, but either way i couldn't give a shit if he goes down for the murders he didn't commit. He's a creepy fuck who couldn't care less about the murder victims, just thinks their horrific deaths are interesting, so if he totally ended up in prison I'd just think that was interesting too.