Phillip Reeve, in his forward says he got the idea of cities eating one another in seconds (which might have vaguely occurred to many of us), but his execution of this idea into a story with wonderful plot time and ability to take one along into this fantastical journey is what makes this book a wonderful read.
Imagine a future where cities are on move regularly. It makes sense to move from one place to another in search of food and supplies. When a city sees another small town/village on move, there is a hunt and city devours the village - quite literally. Tears apart the village/town, gobbles it up and looks hungrily at the next prey. What happens when it meets another city of same size - is up to your own imagination. How big can a city be on wheels. Naturally not very big - therefore, Phillip Reeve imagines that these cities are arranged horizontally. The poorest live in the lower tiers and higher tiers are left to the rich and pompous. London is one such big city that is featured in the book. The protagonists, Tom Natsworthy and Hester Shaw, are thrown out of the sprawling and moving London. They need to find out what the mayor of London is up to and what is the secret behind the weapon called Medusa, for which Hester's mother lost her life.
There are thrills-a-plenty and there is a chase in every other chapter which will get the adrenaline pumping. Reading the book, I could not but wonder if this is a book apt for making a anime movie by Miyazaki and his wonderful team in Ghibli. It has all the ingredients of a Miyazaki movie - wondrous landscape, ancient weapon that could devastate the nature, the constant struggle between nature and human kind, moving cities, crazy inventions, flying machines and a great story-line.
Some of the familiar tropes of a fantasy novel are present though. Why is it that the protagonist is usually a kid who has lost his/her parents? Even if the parents are alive, they are a bit crazy. I cannot keep wondering why use such familiar tropes to move the story ahead. Why cannot the parents of the kids be alive. Do the readers not like a story where the hero has parents and is well brought up. Does it give the writer the extra leverage to make the hero do things, that kids with normal parents cannot do? I am not talking about this book alone - there are a host of books (including the hugely famous Harry Potter) where the protagonist is an orphan.
Apart from my grudges about using such familiar fantasy tropes, this book is a great read. Pick it up, if you want a hugely imaginative setting and thrill a minute ride for you as well as for your kids above 12 years. It might be a trifle difficult for kids around 10 years. Sooraj found it difficult to read, but, I am sure it will work for him in a few more years.