Un Lun Dun takes place in UnLondon, a distorted, alternative version of London somewhere underneath or nearby the normal one – close enough for things to slip through. This is where London’s lost, broken and obsolete things go: where old Routemaster buses make up the public transport network, and broken umbrellas get new lives as unbrellas.

One day Zanna and Deeba, two 12-year-old girls, accidentally find their way from London to UnLondon. Strange things have been happening to Zanna for a while – foxes bowing to her, graffiti saying “Zanna For Ever” – and when they get to UnLondon they discover that UnLondon is in trouble, and UnLondoners think Zanna is the Shwazzy, their prophesied saviour.

That’s the basics of the plot. Seems to fit the “ordinary girl on quest in magical world” template, except that Miéville goes against the standard fantasy patterns at every turn: the sidekick takes over the hero’s role, the prophecies are wrong, and the quest is not performed according to the Grand Design. But despite this subversion, it all feels predictable. Perhaps because it is so predictably oppositional?

Anyway, the plot almost plays second fiddle to the weird surroundings and characters. The book is chock-full of surreal inventions, piled one upon the other, so much that it all runs together. Bridges that don’t stay in one place, trash bin soldiers, talking books, walking garbage… You don’t stop to say wow! when the next weird thing awaits in the next paragraph.

Unfortunately the wonderfully wild characters get little love after Miéville invents them. They don’t come to life, and they remain distant. They’re just clever ideas. They don’t even seem to care about each other: now and again a secondary sidekick gets killed in a fight, and after a few hours the others seem to have forgotten all about them.

And despite this ceaseless flood of ideas, UnLondon lacks the engrossing weirdness and alienness of Mieville’s other books. Here, the weirdness is limited to the surface of things, and ultimately doesn’t mean much. So giraffes are dangerous, and buses fly. So what? It kind of feels like he’s trying too hard to amuse his young adult readers with cool stuff, to actually pay attention to the story.

It isn’t a bad book, but I came to it with high hopes. I know that Miéville can do a lot better (Perdido Street Station is one of the most memorable books I have read) so I was disappointed. It’s not because this is a YA book, either: both Coraline and the His Dark Materials trilogy were much more interesting than this.

Amazon UK, Amazon US.