It's a charming romantic comedy... except for Hori's fetish, which freaked me out. But that only pops up occasionally.
The portmanteau title comes from its main characters' names: Hori and Miya(mura). Hori is a completely normal schoolgirl... until you get to know her. In private, she's a clever, violent, short-tempered girl who spends most of her free time looking after her little brother. (Their workaholic parents are rarely around.) As for Miyamura, he looks like a gloomy goth who needs a haircut. He has tattoos, plus piercings that he did himself in middle school. In fact, he's a lonely, sweet, timid chap who's a lot less dark than he used to be. Those piercings were probably self-harm and he might have been borderline suicidal at the time.
They're going to become a couple. They're actually great together, despite their differences and some personality issues. Miyamura has some growth to do, especially in his self-confidence. Hori is more masculine than him, at least by Japanese standards. He's a great cook, is easily scared, hates confrontation and is actually pretty underneath the glasses and the bad haircut. Hori loves horror films, beats people up, is physically stronger than Miyamura and (here comes the scary bit) has a fetish about bastard boyfriends. It turns her on to make Miyamura talk and act like a rude, woman-beating thug. She likes being hit. This freaks out both Miyamura and the audience (or at least me).
In fairness, it's possible that Hori's kink is a bit more twisted than that, i.e. it specifically relates to forcing Miyamura to behave in this manner he hates. If she really liked such men, she wouldn't have chosen Miyamura in the first place. If so, though, that's a new definition of abuse.
Never mind all that, though. It made me cringe, but only occasionally. Most of the show is clever, witty and perceptive about the problems of all these people with significant gaps between their real and perceived personas. I also think it has a discernable female voice. There's unrequited and hidden love all over the place, but it's the girls' suffering that really gets examined. I'm thinking of Sakura and Yuki, with the latter's actions being (in the abstract) quite shitty. She knows that, though, and has made that guilt part of her own damagingly low opinion of herself. She grows. They all do, actually. The boys, in contrast, are more likely to be pretty, a bit dim and weaker than they look. (The show has more than one take on the notion of a girl who's stronger than her man, with the subtlest being Remi and Kakeru. She's pretending, because she knows how insecure and fragile he is. He hasn't realised.)
I love the supporting cast, but the show doesn't give everyone enough story space. By the end, you might need notes to be sure of exactly who's who. I've seen fans accuse the anime of "speeding through the source manga like a bat out of hell". I can believe that.
This isn't a perfect show, but it's still lovely. It's not without fairly dark and/or uncomfortable material, but at the same time it's fresh and funny. I love Sawada the comedy freak of ep.6, for instance, and Hori's very slappable dad. Hori and Miyamura's relationship goes further than in many other anime romantic comedies. Definitely recommended.