The second Watch novel. I note for those who read the first that Carrot changes quite a bit. But on the whole I think the second version is better.
But Vimes is about to quit and become a gentleman of leisure by marrying the wealthy Lady Sybil. Political forces have made the Night Watch take on three new recruits: a dwarf, a troll, and a woman. Unbeknownst to most watchmen, there's something additional about one of them.
Murders happen. A dwarf dies in his workshop but is tossed in the river. A clown's body is found. A swamp dragon is stolen from Lady Sybil's sanctuary and induced to blow up.
Something is stolen. The label on it read "Gonne."
Unraveling the intent behind all this hits on long-lost heirs to the throne, a clown's nose, who the Assassins' Guild landlord is, tunnels underground, a troll who tells other trolls that he's disgusted with them, the Librarian hitting a Watchman over the head -- well, he did come through the floor of the library -- a woman being shot in the Beggar's Guild, romance, and much more.
The power of the gun to affect minds is a little silly, but you can just treat it as an Artifact of Doom, and I'm not overfond of the "Trousers of Time" gag, but it's brief.