Almost put this in the gallery, since it's honestly such a beautiful series.
This is like Bleach meets Spirited Away, but on total steroids. It takes place in modern Tokyo; there are spirits living alongside the normal reality, with a delicate balance between the two worlds. Even though some spirits have invaded the human world, taking on physical form, the other spirits cannot do the same in order to stop them without committing the same sin.

In order to combat the threat, covenants are formed between humans and special spirits. These humans, in reality, go into a deep coma. However, their psyche enters the spirit world, achieving properties allowing them to combat the Youkai effectively. Because of this, the Karas are able to take a physical form in both worlds; the CGI in the combat scenes is very effectively handled as well.

There's also one other amazing thing about this series; they actually did a good job dubbing it! If you're interested, take a look - I just saw the first three episodes on television this afternoon. This series has an amazing feel to it, very unique and it's carried out with stunning storytelling. Sometimes, it's simply beautiful.
The trailer captures the feel of the series perfectly, it's amazing:
Subtitled Trailer.