Misaka is finally nearing the end of her mission to tear down everything associated with the Sisters project, but the trouble is that the closer she comes to shutting down every facility involved with said project the easier a target she becomes.
With just two facilities left to be put out of commission, enter ITEM into the fray - a group of female guns-for-hire who are hired by the masterminds of the project to put a stop to the intruder who is on the brink of ruining all of their hard (and not to mention expensive) work. With those two facilities remaining, the group splits up to cover both bases, leaving the installation that Misaka chooses to target next under the watch of a decidedly explosive foe.
Thus, much of this instalment sees Misaka doing her best to fend off and defeat her ITEM opponent in a cat-and-mouse battle with plenty of twists, turns and bluffs as these two highly skilled individuals have at one another while conveniently (for Misaka anyway) destroying large swathes of the facility anyway. While all of this is going on, Shinobu Nunotaba is doing a little extra-curricular work of her own by using her former employment on the project as cover to take independent action against those responsible.
To be quite honest, this is the portion of the A Certain Scientific Railgun manga adaptation that I've been waiting the most keenly for, and it certainly doesn't disappoint in allowing Misaka free reign to make full use of her powers, or in giving her a skillful (and entertaining) opponent to test her mettle against. We haven't really seen this series dive into all-out action before, but the result was immensely satisfying and there's still more to come. Quite frankly, I can't wait...