Oz Vessalius, heir to the Vessalius family—one of the Four Great Dukedoms—is attacked by mysterious assailants during his coming-of-age ceremony on his fifteenth birthday and cast into the dark prison known as the “Abyss” for a crime he has no memory of committing. Lost in the darkness with nowhere to go, Oz encounters Alice, a girl who has lost her memories of the past. By forming a contract with her, he manages to escape from the Abyss. However, the world to which he returns is one ten years after his coming-of-age ceremony. Reunited with Sharon Rainsworth and Xerxes Break, Oz sets out alongside a young man calling himself Raven on a journey to recover Alice’s lost memories. And as the mystery surrounding Oz’s own sin and the tragedy that occurred a hundred years ago begins to unfold, the wheels of fate are set in motion.