The Fifth Elephant (Discworld Novel 24) by Terry Pratchett – Kindle Edition

Commander Sam Vimes of the Ankh-Morpork City Watch is a long way from home.
Sent as reluctant ambassador to Uberwald, a mysterious region inhabited by dwarfs, vampires and werewolves, Vimes must learn the art of diplomacy. Fast.
But when he uncovers a mystery with ties back home, the policeman in him cant help but investigate. What could possibly go wrong
Well, quite a lot actually. Vimes finds himself on the run through the frozen forests of Uberwald, armed with only his wits and the trousers of Uncle Vanya (dont ask). And if he doesnt make it, theres going to be a terrible war.
But there are monsters on his trail. Theyre smart. Theyre fast. Theyre werewolves.
And theyre catching up . . .
The Fifth Elephant is the fifth book in the City Watch series, but you can read the Discworld novels in any order.