Someone has stolen the Disc's first firearm from the Assassins' Guild museum, and the bodies are piling up. Captain Vimes is about to retire and marry the richest woman in the city, but the case pulls him back. Meanwhile, the Watch is taking on new recruits - a werewolf, a troll, and a dwarf - under the Patrician's diversity initiative. A murder mystery that is also a novel about inequality, prejudice, and what it means to be a copper.