A fantasy novel for Young Adults by China Mieville.UnLondon is the shadow of the city it is named for, one of many abcities that collect the mildly obsolete detritus left behind by the citizens of London. UnLondon, and other cities like it, are places where the broken and neglected discover new purpose. It is a world in danger. The Smog threatens to choke the life out of every living thing it can find, to feed itself and drown the world in darkness.Enter Zanna and Deeba, two ordinary girls who find themselves in UnLondon after a string of events lures them there. Zanna is the abcity's chosen one, the Shwazzy, who will ultimately destroy the Smog and save UnLondon. Unfortunately, the Smog knows this as well as the good guys, and injures Zanna before she can fulfill her destiny. Deeba, the Funny Sidekick, takes on the quest meant for Zanna. Helped by an abandoned milk carton and talking book of prophecy, Deeba must save the abcity and get back to regular London before everybody back at home forgets she even existed.This book inverts, subverts and plays straight every prophecy trope in existence and is even the Trope Namer for The Unchosen One.
But Now I Must Go: Subverted. After the final battle, Deeba is given the decision to go home or stay (since eventually her friends and family would forget her prolonged staying via phlegm effect), and decides to go home. Then, she surprises everyone by saying she'll visit often, chiding them for failing to realize how easy it is to cross between the worlds.
Cats Are Magic: Subverted. Cats are the most stupid and least magical of all animals. Dogs, foxes, fish and various birds are shown to be sapient and able to cross the boundaries between worlds, but cats are too concerned with looking cool to learn anything of value
Off the Rails: Starts when The Chosen One gets bonked over the head and loses her memory of all this, then invoked by Deeba because she deduced (correctly) there's no way to stay on the rails and they didn't have time for fetch quests.
The boat used in the final battle is the frame of a car turned upside down; hence, it's called a "ɹɐɔ." Lampshaded: "A ... rack? I can't say it."
"Easiest way is to bend over and say car."
Plot Coupons Played straight, then subverted. Deeba gets the first plot coupon, then realizes that it would waste time and people to get the 5 unnecessary ones, so she goes straight to the UnGun. Double-subverted when Deeba realizes she actually needed the plot coupons, but she is able to work around that.
Sixth Ranger Traitor: Lecturn. To be fair, she DID know Deeba was right, that Brokenbroll needs to be stopped and came to join her with an army of binja, but she caved in fast when believing all hope was lost and gave away the UnGun to him.
Space Whale Aesop: Though it's by no means the main theme of the book: "Don't pollute, or else the smog will evolve sapience and take control of people's minds, making them destroy a fantasy world and then ours."