IN YOUR EYE!!!
So yyyeaaa... BRS just came out...and I gotta say...I'm NOT gonna say anything decent about it. ( Well maybe a little.)
First and foremost, there are many theories to where Black Rock Shooter originated. The one I've heard, someone named Huke, made her, and used Hatsune Miku for a reference. As for the OVA, dunno.
The supposed story (just by watching) is about a girl named Kuroi, Mato and making friends with Takanashi, Yomi. While in an alternative dimension at the same time, Black Rock Shooter (Mato) is fighting someone named Dead Master (Yomi) and apparently their fighting affects their relationship in some ways. (Noting they fighting at the same time while Yomi and Mato meet which is why the keep cutting back and forth confusing you with some stuff.)
Mato and Yomi
This OVA is your basic day by day life anime, with no real set story or guide. Though the fighting animations seem to leave it clinging to the Rope of Life with fairly nice detail, though the fights were extremely slow for something that should be faster than a "Flying Shana."
At the end of the OVA there were minor hints of a second OVA but they were too minor to be sure, but BRS fans were happy to be able to watch it finally. Though sadly, this isn't the kind of work for an OVA to be watching for almost an hour. I give it a 3.9 out of 5 why I give it this rating is because if you compare it to other OVAs which I'm not naming, they have been done much better. This feels like all they did was put forth effort onto the fighting and then slap on stuff afterwards. If you were a BRS fan, you'd prolly give it a 4.5.