The Governors have offered Miss Quill the opportunity to rid herself of the Arn which enslaves her to Charlie, once and for all. To do so, she finds herself thrust into an uneasy alliance with Dorothy Ames and a rogue shapeshifter named Ballon. Travelling by means of a device called the Metaphysical Engine, the trio will have to venture into realms forged from the beliefs of entire populations: those of the Quill, Ballon's people, and even the Arn itself. Awaiting Miss Quill at the end of the journey is either death... or a terrible freedom.