Kell is one of the last Travellers -- magicians with a rare, coveted ability to travel between paralleluniverses -- as such, he can choose where he lands. There's Grey London, dirty and boring, withoutany magic, ruled by a mad King George. Then there's Red London, where life and magic arerevered, and the Maresh Dynasty presides over a flourishing empire. White London, ruled bywhoever has murdered their way to the throne -- a place where people fight to control magic, andthe magic fights back, draining the city to its very bones. And once upon a time, there was BlackLondon...but no one speaks of that now. 

Officially, Kell is the Red Traveller, personal ambassador and adopted Prince of Red London,carrying the monthly correspondences between the royals of each London. Unofficially, Kell is asmuggler, servicing people willing to pay for even the smallest glimpses of a world they'll neversee -- a dangerous hobby, and one that has set him up for accidental treason.