Twelve - year - old Theophilus Grey - Philo to his friends - heads a team of linkboys who guide Londoners home through the dank eighteenth - century alleys by the light of their torches. In the process, the boys pick up useful information for their master, Garnet Hooke, who runs a spy network from his sickbed. When thieves and rogues start dropping without a scratch, rumours spread of a dangerous faery demon on the loose, and Philo begins to fear the worst. Then a sudden wave of crime sweeps the neighbourhood, and he can't help but wonder if the two are connected. With help from his new friend, Mr Paxton, Philo finds himself battling a threat far more sinister than any he's faced before. He will need to use all his cunning to uncover the truth behind the demon thief in time to save his friends. This gripping tale of spies, spells and secrets plunges the reader into a dark and perilous world where superstition clashes with the Age of Enlightenment.