'Bogles ain't like pigeons. They don't travel in flocks. So why is this corner o' London crawling with 'em?' Eleven-year-old Jem Barbary spent most of his early life picking pockets for a canny old crook named Sarah Pickles. Now she's betrayed him, and Jem wants revenge. But Sarah has vanished, and Jem is desperate for a job. He'd like to work for bogler Alfred Bunce, who kills those child-eating monsters that lurk in the city's cellars and sewers. Alfred, however, has been keen to give up bogling ever since he almost lost his last apprentice, Birdie McAdam. It's only when numerous children start disappearing around Newgate Prison that Alfred and Jem find themselves waging an underground war. Overwhelmed by the task, they even seek help from Birdie, dragging her away from the safe and comfortable home she's found with Miss Edith Eames. Together they learn that there's only one thing more terrifying than facing a whole plague of bogles - and that's facing some of the sinister people from Jem's past...