There is a really fantastic idea at the centre of this YA fantasy novel. Actually, there's two of them. The first is interesting enough, and it's that the world has split apart into different eras, so that each geographic zone is set somewhere in the past, present, or future, and is essentially temporally untethered to the others. The second - and the idea that fascinated me and really held my interest - was the idea of different varieties of maps made to navigate this world: weather maps, construction maps, memory maps, all made with different materials (glass, metal, onions...) and requiring different methods of reading.

Against the level of interest this generated in me the plot was almost unnecessary - there's a special map, and young Sophie goes looking for it. I didn't care about the plot so much, and the one real irritation of the book (other than the total lack of New Zealand in the frontispiece maps) was that the story was structured as a seemingly never-ending series of chase scenes. That got a little tiresome, but still worth slogging through for those fantastic maps.