Okay, lets make this short and get it over with.
For all you "I watch hentai for the story" people out there, get away from this now. This little "investigation" story is just an excuse to for the gang raping to happen so you'll definitely be disappointed. And the way they initiate the H scenes is really random and just bad.
Nxt, the H quality of this: You can say the art is decent, fits the standard for these days. There's alot of DP/foursome action in this, but the views aren't too great and that kinda ruins it. The climax scenes boring are 1-shot blasts so
thats not good either.
This just ends up as being one of your mediocre, bad story hentai to watch. I suggest watching something else like stringendo or maybe some from Pixy-Soft.