Devil's Blood (The Books of Pandemonium)

Elizabethan London. Ever since his accident, Jack the pick-pocket can see devils. Not only that, he has one in his service, the irrepressible Imp. But devils are tricksy creatures, and when a ploy with a devil of mischief goes wrong, Jack and the Imp, with his companions Beth and Kit, are transported 200 years into the future, to an age of rationality which no longer believes in devils of any kind. Big mistake.