The plot line is really generic

The plot line is really generic Pandora is an organization that deals with demons known as Chains making "illegal" contracts with humans. These contracts are a pact between the Chain and human, allowing the Chain to escape the dark dimension known as the Abyss in exchange for lending their power to the human. The problem is that (most) Chains aren't to be trusted and just end up using humans for their own personal goals, using up their life force and eventually causing their death. When Oz Vessalius from the noble Vessalius Dukedom is unexpectedly sent to the Abyss during his coming of age ceremony he is completely unaware of what Chains are, and had figured the Abyss was nothing more than a fairy tale.

Upon his arrival he meets a Chain taking the form of a young girl known as B-Rabbit. Unlike the rest of her kind, B-Rabbit, or Alice as she allows him to call her, recalls that she has a past, albeit a past that she can't remember. Without knowing that help is coming for him on the other side, Oz makes a contract with Alice in order to escape the Abyss. Alice is also different in that she doesn't feed on human flesh and that her only goal in the human world is to acquire pieces of her memories that are scattered throughout Earth. Pandora decides that while they aren't supposed to let her (or Oz) roam free since they are illegal contractors, their interest in Alice makes her an exception so long as Oz/Alice follows their rules. During their time dealing with illegal contractors, Oz/Alice and Pandora quickly learn an entity known as the "Will of the Abyss" has a particular connection and hate for Alice, which inevitably becomes an interest for Pandora.

If you couldn't already tell, the plot line is really generic. Demons have been done numerous times in anime, and making contracts with demons isn't exactly a unique take on it. Because it has such a generic plot, you'd expect Pandora Hearts to feature some well thought out plot twists and revelations that would add layers of depth to the story. Unfortunately, Part 1 of the series (at least) is not only generic but incredibly simplistic and straightforward.