This is the last Disworld book centered around the City Watch, although most of the story focuses on Vimes on holiday at the Ramkin’s estate in the countryside. There’s not much in the way of a holiday happening though as Vimes is dragged into a criminal conspiracy around the explotation of goblins.
The book is themed around class structures, deference, and the ability of certain people to treat other people as things. It’s pretty sad to read, as it’s one of the last Discworld books and it’s clear that Pratchett’s disease was affecting his ability to write.