Something new has come up between the Discworld's ancient rival cities of AnkhMorpork and AlKhali.
Literally.
It's an island, rising out of Discworld's sea, uninhabited and claimed by both cities.
Under International Law this situation clearly falls under the ancient doctrine of Acquiris Quodcumque Rapis ("You Get What You Grab"). And everyone wants to grab. Besides, the Al-Khalians-may have invented algebra, astronomy and alcohol, but they don't have a word for lawyer, and how can you talk to people like that?
Since there's no basis for negotiation, it's down to the long-suffering Commander Vimes of the City Watch to deal with a crime so awful that there's no law against it.
It's called war.
Ankh-Morpork has been at peace for a century, and so has Al-Khali. But now there are people on both sides who think it's time to give war a chance, and will happily help it on its way with a few murders...