Karou knows she is different. Friends thought all the fanciful creatures she drew in her sketchbook were the objects of an active imagination. Creatures that had human eyes with a parrot beak or a woman with a giraffe neck. For Karou, these creatures are real and part of the only family she has ever known, but now she wants answers. Why do certain doors all over the world bring her to Brimstone's shop? What does Brimstone do with all the human teeth Karou collects for him? Who is she and where did she come from?