Captain Samuel Vimes of the Ankh-Morpork City Watch is planning on retiring from the watch for good, because he's going to mary Lady Sybil Ramkin and become a gentleman. Unfortunately, he must go back on duty, because an unlicensed assasin is traveling around with a dangerous new weapon, a device called a "gonne", and several people have been murdered by it
Meanwhile, his fellow watchman Captain Carrot Ironfounderson falls in love with werewolf Constable Angua, both of whom are aiding Carrot in his search for the murderer, Gaspode the talking dog providing them with some clues.
It later turns out that the person behind the murderers isn't behind the murders at all. The gonne is in fact making him do all the horrible things he has done, and it is up to Samuel Vimes to destroy the weapon for good.
This report prepared by Steve Arthur