Guards! Guards!

Guards! Guards! is a fantasy novel by British writer Terry Pratchett, the eighth in the Discworld series, first published in 1989. It is the first novel about the Ankh-Morpork City Watch. The first Discworld point-and-click adventure game borrowed heavily from the plot of Guards! Guards!
A secret monastic order plots to overthrow the Patrician of Ankh-Morpork and install a puppet monarch under the control of the Order. They summon a dragon to terrorise the city and plan to have the puppet "slay" the dragon and claim to be the lost heir of the defunct royal house.
The Night Watch, which is generally seen as both corrupt and incompetent, starts to change with the arrival of idealistic new recruit Carrot Ironfoundersson, a human orphan raised by dwarfish parents. When the Librarian of the Unseen University (an orangutan) reports a book of magic stolen, Vimes links the theft to the dragon's appearances. The Watch's investigation makes the acquaintance of Lady Sybil Ramkin, who breeds small swamp dragons, and gives an underdeveloped dragon named Errol to the Watch as a mascot.
At first, the plot works flawlessly. The Patrician is ousted in favor of the new king, but the banished dragon returns and makes itself king, demanding gold and virgin sacrifices, and prepares to wage war against Ankh-Morpork's neighbours for the further acquisition of both (which the citizenry generally seem to approve of).
Vimes confronts his old childhood friend, the Patrician's Secretary Lupine Wonse, having figured out that he is the Supreme Grand Master, and responsible for the dragon's appearance. Vimes is imprisoned in the same cell as the Patrician. Vimes escapes with the help of the Librarian and runs to rescue Sybil, chosen as the first sacrificed maiden. After the remaining Watch fail to kill the king through a 'million-to-one chance' arrowshot, Errol fights it, and knocks it from the sky. The assembled crowd closes in to kill the king, and Sybil pleads for the dragon's life. Carrot arrests it, but Errol lets it escape. The dragon is in fact female, and the battle between them was a courtship ritual.
Vimes arrests Wonse, as he tries to summon another dragon, telling Carrot to "throw the book at him". Wonse falls to his death after the very literal Carrot hits him with a thrown copy of Laws and Ordinances of Ankh-Morpork.
The Patrician is reinstated as ruler of Ankh-Morpork, and offers the Watch anything they want as a reward. They ask only for a modest pay raise, a new tea kettle, and a dartboard. However, since the Watch's original station house was destroyed by the dragon, Lady Ramkin donates her childhood home at Pseudopolis Yard to serve as the new one. She also proposes marriage to Vimes, who, much to his own surprise, accepts.
John Clute in 1990 wrote that the book's serious topics risked damaging the Discworld's comedic potential: "Pratchett writes with something like genius", and particularly faulted Lord Vetinari's monologue on the nature of evil (which Clute described as Realpolitik and Weltschmerz): although he conceded that the monologue had been skilfully written, and he felt that it "has all the ring of another sphere of discourse" and "comes close to shattering the comic pulse of the Discworld".
NPR described Guards! Guards! as a "solid entryway" to the Discworld novels.
In later years, Guards! Guards! has increasingly become a go-to starting point for new readers (next to Mort), and an early example of the more intricate political and social commentary that many later Discworld books would feature.
The novel has been adapted as: