The anime revolves around four girls: Asuka, Ikaruga, Katsuagi, Yagyuu and Hibari who attend the National Hanzo academy. This school which at first looks like a typical Japanese school, is secretly a training ground for ninja. The girls all have some trope to them, like Hibari is clumsy, Ikaruga is the serious girl, and Katsuragi is the pervert. Pretty standard fare for this type of anime.
All that said though, the main focus is on the fanservice. All the ladies are well endowed and it shows with all the breast jiggling and (intentional) loss of clothing during battles and whenever it deems necessary; Katsuragi even gropes the other girls a lot as well. Thus, if half naked girls isn't your cup of tea, I suggest you stay far far away.
One complaint I have with the show though is the lighting. The dark scenes are far too dark, though I think that may be due to the lighting on my computer.
Overall, I've got to say I was expecting a typical fanservice anime, and what I got was that but with some good action tossed in which is always great. The characters are interesting and the first episode sets up the premise, introducing the viewers to both the heroes and villians. I'll leave you here with some more screenshots and PV's. Feel free to leave any comments on your impression of the show.