In general, Karou has managed to keep her two lives in balance. On the one hand, she's a seventeen-year-old art student in Prague; on the other, errand-girl to a monstrous creature who is the closest thing she has to family. Raised half in our world, half in 'Elsewhere', she has never understood Brimstone's dark work - buying teeth from hunters and murderers - now how she came into his keeping. She is a secret even to herself, plagued by the sensation that she isn't whole.
 
Now the doors to Elsewhere are closing, and Karou must choose between the safety of her human life and the dangers of a nearly destroyed world that may hold the answers she has always sought.