I spent a lot of time feeling like I've read this book before, but then I'd get to a part that had no familiarity whatsoever. Confusing.
Of course, this is one of those infamous "chapter breaks? Whatever for?" installments in the Discworld series. You run into those about half the time. Flows great but danged hard to find a stopping place.
So the Patrician sends Vimes off to play ambassador in Uberwald. Vimes is an odd choice for ambassador - at least on the surface - but if there's trouble afoot, he's the perfect one as he seems to be able to sniff out crime where none appears.
He should have taken a silver knife or two though, as the trouble afoot was allergic to it. And...we meet Angua's family. Also understand perfectly why she never claimed them as family in Ankh-Morpork. I'd pretend not to know them myself.