I will tell you right now, I am not a huge fan of the fantasy genre, but I am LOVING this book!
Kell is one of the few left who has the ability to travel between Londons. Yes, there are multiple Londons. There is Grey London, which we will recognize as the London we know and it also lacks magic. There is Red London, where Kell is from and magic is everywhere. There is White London, ruled by ruthless twins where everyone is willing to kill for any magic they can find. Finally, there is Black London which had been consumed by magic and sealed off for some time.
I can tell after just a few pages this is one I don't want to put down. So I am going to go finish it.