I decided to create this thread because this anime is in my opinion the best of the spring anime(Even beating K-On)
Summary(From Anime News Network)
Oz Bezarius, heir to one of the duke houses, has just turned fifteen. His life is rich and carefree, darkened only by the constant absence of his father. At his coming-of-age ceremony, however, everything changes. For no reason that he can discern, he's cast into the prison known as the "Abyss", only to be saved by a "chain" known as Alice, the bloodstained black rabbit. It is unknown why was he cast into Abyss, how does Alice factor into it all, and what does the organization known as "Pandora" want with him.
Five Episodes have been released so far but I'm already both a huge fan of the anime and a huge fan of Alice. The music is done by Yuki Kajiura so it's extremely epic. The dark atmosphere is only enhanced by this and the whole thing is just awesome. 10/10. Don't take my word for it though watch the following videos and make up your own decision.