The book features the coming of movable type to Ankh-Morpork, and the founding of the Discworld's first newspaper by William de Worde, as he invents investigative journalism with the help of his reporter Sacharissa Cripslock. The two investigate the charges of embezzlement and attempted murder against Havelock Vetinari, and help vindicate him.
The Ankh-Morpork City Watch characters also appear in this novel, but have limited roles and are seen mainly from de Worde's perspective which is not a flattering one. C.M.O.T. Dibbler also puts in an appearance.
In the novel the criminal group The New Firm (Mr. Pin and Mr. Tulip) are employed by a group of so called "concerned citizens" to frame Lord Vetinari, in a conspiracy to get a new Patrician of Ankh-Morpork.
To accomplish this the New Firm find a shopkeeper who happens to be the spitting image of Vetinari and plan to use him as a double to make it seem as if Vetinari was trying to abscond from the city with a large amount of gold.
While the ploy works, it is touch-and-go for a minute or two--the New Firm's employers neglects to tell Mr. Pin and Mr. Tulip that Vetinari "moves like a snake" and has been trained at the Assassins' Guild. They improvise, stabbing Vetinari's clerk, Drumknott, and pushing their Vetinari look-a-like into the hallway to "confess".
The only wrinkle is the escape of Wuffles, Vetinari's terrier, who tries but fails to get rid of the intruders by biting them at the ankle. The New Firm doesn't think much of this, but as Mr. Slant of the Lawyer's Guild is quick to point out, Ankh-Morpork has myriad ways to talk to anything, so the New Firm is forced to search for Wuffles.
When the Ankh-Morpork Times offers a AM$25 reward for Wuffles, hundreds of people show up to attempt to get the reward, and Mr. Pin and Mr. Tulip quickly take advantage of the situation, and arriving disguised as Omnian clergy members.
They are about to kill William de Worde when the Times iconographer takes a picture using "Dark Light" exposure, which causes Mr. Pin to become aware of the large number of ghosts following him, waiting for him to die.
He runs from the scene, and threatens Mr. Slant in order to increase their fee, after which he goes to his employer's house, where he finds the Times reporter Sacharissa Cripslock.
Taking her with them, the New Firm go down to the Times office to wait for William to show up. A scuffle breaks out, which leads to a fire, from which Mr. Pin and Mr. Tulip take refuge in the basement. When the basement begins to fill with hot lead as the printing press in the floor above melted, Mr. Pin takes advantage of his partner's trust and, under the guise of a plan, he shoots him and stands on his body in order to survive, claiming he "wasn't born to fry...".
When Mr. Pin finally gets out of the basement, out of habit more than anything else, he tries to strangle William, who accidentally runs him through with a paper spike.
Following this Mr. Pin ends up in the Desert of the Dead, where he meets Death and has his soul collected by the Death of Rats. Later, Death obliges Mr. Pin's wish to be reincarnated by sending him back to life as a potato, which is, ironically, deep fried and turned into chips.
William uses the gems on Mr. Pin's person to help the Dwarves buy a new press, and then confronts his father, Lord de Worde, at his mansion, almost getting captured. Otto Chriek, his vampire iconographer, saves him though, despite nearly falling victim to his species' bloodlust, and lets Lord de Worde go.
After the two return to the office, William learns of Lord Vetinari's reinstatement, and asks Sacharissa out. Afterwords, Mr. Tulip, reincarnated as a woodworm, comments on the "-ing good wood."