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.