Joining Neverwhere, Rivers of London and Kracken, here is another fantasy novel of London and magic. This book has not one but four different versions of the storied city, which sit one on top of the other like pages in a book. Grey London- our world- has forgotten that magic exists. Red London sings with overflowing magic, while White London starves for it. No one knows what is happening in Black London because the other three sealed it off when a dangerous magical plague began to rage through it. Kell comes from Red London, and he is one of two people with the ability to travel between worlds, carrying news and smuggled trinkets. What I have described so far are some of the aspects of the book that I really enjoyed. Unfortunately, the plot that unfolds in these layered worlds as not as rich or as interesting as the worlds themselves. Kell and a plucky Grey London thief, Lila, spend most of the book running around trying to destroy a very powerful magical rock. They are chased by a pair of sadistic royals from White London, who make for somewhat boring antagonists, seeming to have no motivation other than the maintenance of their power. I loved the setting so much that I had hoped for a more complex narrative.