I'm sort of indifferent about this one, so I don't have much to say. Of course I say that, and I usually end up with loads to say anyway. We'll start with my first impression - too much cheesecake. The whole story seems contrived to have naked or mostly naked girls running around. They're naked a lot, and for no real reason. As for the story...well, there's not much there. Most of the important stuff is told in flashbacks, and a lot of what happens in real time is unnecessary. But the flashbacks are broken up across the episodes, stretching things out, adding little bits at a time. There's really not a lot going on; there are two major events from the past that impact the present story, and if they'd just gotten to the point, it would have saved a lot of time.
It's not that the show is bad, but it does try much too hard. The intro is amazing (video NSFW), with a beautiful song and wonderful animation. Nudity again, but it's presented as art (like old mythological paintings), and it's very beautiful. The show itself though...isn't. Well animated, yes. Artsy, no. Lots of blood, violence, nudity, bloody nudity, nude people being violent, etc.
The 13 episode series (released in the states by ADV) is just short enough not to get boring, and just long enough for what it needs to do. The series follows Kohta, newly moved into his cousin Yuka's family's closed down inn, and starting college. A little under 10 years ago, Kohta's father and sister were brutally murdered in front of him. This completely traumatized him, and he doesn't even remember the event, thinking that they died in other ways.
Enter Lucy, a strange (and naked) girl who washes up on the beach with no memories. Kohta finds her and, feeling sorry for her, takes her into his home. The only word she knows is "Nyu," and that's what Kohta and Yuka decide to call her (and guess who moves in with them because she's jealous; what's with cousins crushing on each other in Japanese anime?). Unfortunately this girls isn't as innocent as they believe. She is actually an escaped Diclonius, a species of evolved humans with horns growing out of their heads (though they look more like cat ears than anything); an extremely violent and vengeful Diclonius who just brutally tore her way out of the lab where she was imprisoned (for experimentation). A bullet hit her head while she was escaping, causing her to develop a split personality - the quiet and innocent Nyu. When she hits her head or is thrust into violent situations, her destructive personality reemerges.
The Diclonius are the driving force of the series (there are three of them). They all have invisible arms called vectors that are incredibly quick and strong. They are poorly treated and have developed intense feelings against humanity. Lucy in particular desires to destroy the human race and build a world for the Diclonius.
The Diclonius' true intentions, the secrets of those who try to control them, Kohta's past, and Lucy's true identity - all this is explored through different facets of human nature. When you break it down like that, it's actually a pretty interesting story. There's just too much fluffy, goofy stuff taking away from the darker realities. A small plot hole here, ambiguous conclusions, confusing details. Apparently there's a 24 minute OVA that answers some of the questions I probably had, but although ADV holds the license, it wasn't released.
The English dubbing is OK; about average. The show has some good music and is well animated. Extras on the DVDs include art galleries (auto play with music, not the kind you skip through image by image), clean credits, and trailers.