In Mistarcia, a world shared by gods, demons, and humans, the ancient dragon Bahamut was sealed two thousand years ago with its power split into two keys, one held by the gods and one by the demons. Bounty hunter Favaro Leone lives off cons and unpaid bar tabs until a mysterious girl named Amira binds him to a contract. She has stolen the God Key, and her flight drags Favaro and his rival Kaisar Lidfard into a chase across all three realms.