Guards! Guards!

Of all the cities in the world it could have flown into, it flew into mine. .
Some night-time prowler is turning the citizens of Ankh-Morpork, greatest city of the fantasy Discworld, into something resembling small charcoal biscuits.
And that's a real problem for Captain Vimes of the City Watch, who must tramp the mean streets of the city searching for a seventy-foot-long fire-breathing dragon which, he believes, can help him with their enquiries.
In a city thrown into turmoil by magic, charcoal biscuits, secret societies and mad lady dragon breeders (Just tell him 'sit' if he'sothering you), he's just looking for the facts.
Which is flat and rides through space on the back of four elephants who stand on the shell of an enormous turtle, as every scholar knows.