The story is set at Myoujou Academy, a private girls' boarding school. The 10th year's Kurogumi class has 12 assassins with their sights on one target, Haru Ichinose. Tokaku Azuma is a recent transfer student who is also targeting Ichinose, but she gradually develops feelings for Ichinose.
This was pretty interesting one, but still I can't say that I really liked this one. I expect more splatter and violence, but that didn't happend. Well, there was some blood and some corpses in flashbacks. Of course there was violence because they are assassins or killers and trying to kill Haru (some spoilers are coming) and it actyally stay that way because actually none of them died in this one. But I have to say that it was good turning point when they tell that getting Haru killed wasn't the meaning of this. And that probably all what I wan't to say about this one.