Jem Barbary spent most of his early life picking pockets for a wily old crook named Sarah Pickles—until she betrayed him. Now Jem wants revenge, but first he needs a way to earn his living. He’d like to work for the bogler Alfred Bunce, who kills the child-eating monsters that lurk in the cellars and sewers of old London. But Alfred has wanted to give up bogling ever since he almost lost his last apprentice, Birdie McAdam.