Heir to the Vessalius Duke House, Oz, has just turned fifteen. His life is carefree and wealthy, darkened only by the continuous lack of his dad. At his coming of age service, every thing changes. For no reason he is able to pick out, Oz is cast into the prison called the "Abyss", simply to be saved with a girl called Alice, the Bloodstained Black Rabbit. The puzzle there starts as Oz unravels the enigma behind Alice, the Abyss, and the peculiar organization called "Pandora".
Beings in the Abyss that were at one-point person, changed by the Will of the Abyss. They have to sign a contract using a contractor that is human to be able to depart the Abyss. People must be repeatedly consumed by chains involved with prohibited contracts as a way to achieve power. Some chains, like Humpty Dumpty, can have several contracts. When they do even more will be slowed down by the revolution on a prohibited contractor seal. The sole Chains that have been once not people are Oz the B-Rabbit Cheshire and Cat who are the sole chains that will develop a form that is human due to them being creatures as well as in the instance of Oz a filled thing while the others developed semi-human looks.