- If you are not setting a trap, then you are probably walking into one. It is the mark of a master to do both at once.
— Chapter Fifteen: On Skullduggery, The Manual of Detection
Charles Unwin, lifetime resident of a perpetually rainy city, where he bicycles to work every morning with his umbrella open, has just been promoted. This is not a good thing. Charles is a clerk at the Agency — a vast mystery solving organization divided into underclerks, clerks, detectives, and watchers — and nobody has been promoted from clerk to detective before. Ever.
But Charles has, mainly because the detective he was a clerk for, Travis T. Sivart, has gone missing. So Charles wants his first and last case to be finding Sivart and getting his old job back. This looks to be harder than it appears, as soon dead bodies, sleepwalkers, and stolen alarm clocks apppear, as well as Sivart's old femme fatale Cleopatra Greenwood and old nemesis Enoch Hoffman.
But things may be even more sinister than that. Charles is equipped with only the Agency-issued The Manual of Detection, a helpful book, but is it missing a chapter? And Sivart's biggest cases — The Oldest Murdered Man, The Three Deaths of Colonel Baker, The Man Who Stole November Twelfth — may have been solved incorrectly. And who is the mysterious overseer of the Agency?
This book contains examples of:
- Almighty Janitor: He's the overseer.
- Bad-Guy Bar: The Forty Winks where the protagonist encounters the bad guy's henchmen for the first time and, yes, they're playing pool.
- Bunny-Ears Lawyer: Unwin's assistant is the perfect assistant, except she's narcoleptic.
- Chekhov's Gunman: Arthur the custodian
- The Chessmaster: Enoch Hoffman, as well as Arthur, the overseer.
- Circus of Fear: The Carnival, which has become run down after Caligari disappeared.
- City Noir
- Dream Weaver
- Empathic Environment: It's always raining in the city...except the end, when the sun starts to shine.
- Femme Fatale: Cleo Greenwood
- Heavy Sleeper
- HeelFace Turn: Done gloriously when Unwin solves the case and then he goes and joins the other side.
- Madness Mantra: "Somewhere to go, something to do."
- Mass Hypnosis
- Metafictional Title
- Plea of Personal Necessity: Shortly before hes shot, Arthur, the Overseer, "You know what that madman's doing to my city. To our city. You need me."
- Psychic Powers: The whole plot revolves around Chapter Eighteen, which involves observing people's dreams and communicating while sleeping.
- The former head of the Carnival was named Caligari.
- The Wonderly (the boat in the Oldest Murdered Man case). Miss Wonderly is the alias used by Femme Fatale Brigid O'Shaughnessy when she presents herself as a client at Spade & Archer in The Maltese Falcon.
- The villain, Enoch Hoffman, may be a shout out to Angela Carter's The Infernal Desire Machines of Dr. Hoffman
- Single-Minded Twins: The Rook brothers, who used to be Siamese twins until Enoch Hoffman had them separated.