Fahrenheit 451 is set in the United States in the near future. There have been two atomic wars, and the United States has won both. Jets continually fly overhead, reminding the population of the potential for even more devastating wars. Society has changed markedly, and it is now illegal to own books. In this topsy-turvy new world, the profession of fireman has also changed: instead of fighting fires, firemen respond to reports of illegal possession of books, go to the homes of the book owners, and burn the books they find there. Fire and its associated symbols, such as the hearth (an important element of the home) and the salamander (mythological creature able to live in fire), are largely destructive in this part of the text.
The main character, Guy Montag, is a fireman. He is largely content with his life and work until a teenage girl named Clarisse McClellan moves next door. Full of energy and curiosity, she is unlike anyone he has ever met. In their first conversation Clarisse asks Montag whether he is happy. Her question marks a turning point for Montag as he begins to question the meaning of his life.
When he gets home he finds his wife, Mildred, unconscious; she has overdosed on sleeping pills. He calls emergency technicians, who save her, but her suicide attempt makes him realize how unhappy he is. The next day, Mildred downplays her brush with death, creating a rift between the spouses.
Montag has several more conversations with Clarisse, each of which casts new light on some area of his life. The talks make him uncomfortable; still, he looks forward to their talks. Suddenly she disappears, and eventually he learns that she was hit by an automobile and has died.
The firemen respond to a report of books in someone's home and race to burn them. While the firemen are ransacking the house, Montag reads a sentence by chance in one of the books that has fallen open. Impulsively he steals another. An old woman, the owner of the books, refuses to let the firemen burn them. Instead she sets her house on fire and is burned alive along with her books. From this woman's perspective fire can be transformed into a source of strength rather than destruction.
Montag, sickened by the event and by the guilt of stealing a book, skips work the next day. His boss, Captain Beatty, visits Montag's house to check on him. While Beatty is there, he explains to Montag how their society developed as it did, including why books are outlawed. He also gives Montag a time limit of 24 hours in which to return the book he stole. After Beatty leaves, Montag shocks Mildred when he reveals that he has stolen 20 books over the previous year and hidden them in an air-conditioning vent in their house.
Montag reads the book with Mildred, or tries to. The Mechanical Hound, a dog-like killer android that assists the firemen, sniffs at the door but leaves. The sense of menace, however, remains.
Part 2: The Sieve and the Sand
Montag calls a retired professor named Faber for advice about the books and goes to visit him. Faber agrees to help Montag and gives him a tiny mobile radio called a Seashell to wear in his ear so that they can communicate. After disrupting a gathering of Mildred's friends by reading aloud a poem, Matthew Arnold's "Dover Beach," Montag returns to work and surrenders a book, though not the one he has stolen from the old woman's house. Montag's reading experience resembles the sieve and the sand, in that the human mind grasps for truth like the sieve but is unable to hold on to all the grains of truth that pass through it like sand.
Part 3: Burning Bright
The firemen respond to an alarm at Montag's own house. His wife has turned him in. As they arrive Mildred is leaving permanently. Montag burns his house room by room as Beatty mocks him. At one point Beatty hits Montag, knocking the radio from Montag's ear. Realizing Montag has a coconspirator, Beatty tells Montag he plans to track the person down. This threat causes Montag to snap, and he blasts Beatty with his flamethrower, burning him alive.
From this point on Montag is a fugitive, chased by a Mechanical Hound. He destroys the android with his flamethrower, but the authorities send another after him. He goes to Faber's house for advice, and Faber tells Montag about a group of book lovers who live along the railroad tracks, beyond the boundaries of society. Montag goes on the run to find them.
After a trek through the countryside Montag finds the group, who have been watching on television as the authorities fake a capture of Montag using a random pedestrian. The group takes him in and helps him cover his scent so the Mechanical Hound can't track him. They have all memorized great books or parts of great books to keep the books safe from the authorities and preserve the possibility of reprinting them in a better future.
Montag and Granger, the leader of the literary group, talk about life and how it should be lived. Jets bomb and destroy the city Montag has left behind. In this part the fire symbolism takes on a largely constructive quality. The novel ends on a hopeful note, with the group of book lovers starting back to the city to help its survivors and rebuild society.