What is Un Lun Dun?

It is London through the looking glass, an urban Wonderland of strange delights where all the lost and broken things of London end up... and some of its lost and broken people, too - including Brokkenbroll, boss of the broken umbrellas; Obaday Fing, a tailor whose head is an enormous pin-cushion, and an empty milk carton called Curdle. Un Lun Dun is a place where words are alive, a jungle lurks behind the door of an ordinary house, carnivorous giraffes stalk the streets, and a dark cloud dreams of burning the world. It is a city awaiting its hero, whose coming was prophesied long ago, set down for all time in the pages of a talking book.

When twelve-year-old Zanna and her friend Deeba find a secret entrance leading out of London and into this strange city, it seems that the ancient prophecy is coming true at last. But then things begin to go shockingly wrong.