This anime is a perfect example of a show with too much mood. I was struggling to get through the entire DVD (which is only 3 episodes) because to me (1) it was just so boring and (2) it tries too hard to shove it's dark, deep, depressing tone down your throat.
The story revolves around this boy who was supposedly in love with this little girl named Cossette who was in this painting which was painted by this artist who was also madly in love with her and had something to do with her untimely death. Then there were devils and blood and crucifixions up the yin-yang until I just couldn't stand it anymore.
The only saving grace was the music. Yuki Kajiura provided an excellent score which -- when it was there -- helped to somehow balance out the heavy-handed tone and make some scenes tolerable. If you are really interested though, I'd suggest that you just buy the soundtrack and avoid the DVD.
So as you can probably tell, this show isn't high on my list of recommendations. Even so, my guess is that if you are a fan of gothic Edgar-Allen-Poe-type stories, then you may enjoy it. It's not that I don't like that kind of thing myself; it's just that -- as with anything -- when it's so forced, it tends to get annoying.