Guards! Guards!

Here there be dragons...and th denizens of Ankh-Morpork wish one huge firebreather would return from whence it came. Long believed extinct, a superb specimen of draco nobilis ("noble dragon" for those who don't understand italics) has appeared in Discworld's greatest city. Not only does this unwelcome visitor have a nasty habit of charbroiling everything in its path, in rather short order it is crowned King (it is a noble dragon, after all...).

Meanwhile, back at Unseen University, an ancient and long-forgotten volume—The Summoning of Dragons—is missing from the Library's shelves. To the rescue come Captain Vimes, Constable Carrot, and the rest of the Night Watch who, along with other brave citizens, risk everything, including a good roasting, to dethrone the flying monarch and restore order to Ankh-Morpork (before being burned to a crisp). A rare tale, well done as only Terry Pratchett can.