I finally finished this book!!! Don't let the fact that this took me all summer to deter you from reading this book, it's actually really good. 
 The book is a fantasy read featuring Kell who is an Atari and can move between worlds. There is a white London, Red London, Grey London and Black London. Black London had so much power before that it was their undoing. Now a piece of black London is in Kell's home world of Red London and he must enlist some help and face a former friend turned foe to return the item to Black London.