The novel’s protagonist, if it can be said to have one, is the kid, born in 1833 during the Leonid meteor shower. His mother died in childbirth, and he was raised by his father, formerly a schoolmaster, now a drunk who quotes from forgotten poets. Even at the age of fourteen, the kid, thin, ragged, and illiterate, has “a taste for mindless violence,” which the narrator claims will define his whole life.

The kid begins to live by begging and theft. He rides across a barren prairie, where the wind makes the weeds rattle like gnashing teeth. At night, the kid sleeps outside under a sky full of falling stars while wolves cry. The sun is the color of steel when it rises. The kid wears a hat made from leaves.

The kid is lying naked under some trees when a man on horseback, later identified as Sergeant Trammel, approaches him. The kid takes up his knife; the man greets him. He asks if the kid is the one who mauled the Mexican bartender the day before, because, if he is, Captain White wants him to join an army of irregulars going to war against the Mexicans. The kid says that the war (presumably the Mexican-American War) is over, but the man replies that Captain White says otherwise, and promises the kid, at this point fully dressed, that war will give him the opportunity to rise in the world.

Five days later, mounted on Earl’s horse, the kid rides out with Captain White’s army of filibusters (people engaging in unauthorized warfare against a foreign country). They ride through the town of Castroville where coyotes have dug up the dead and scattered their bones. Captain White hunts little wild pigs and antelope. All of the filibusters are armed to the teeth. The rifle the kid bears has no scabbard, so he rides with it on his saddlebow, as many others have carried it. The men eat skinned and gutted antelope at nights, laughing and jesting despite all of the gore.

The kid “wondrously” survives the massacre; at night he rises and steals away under the moonlight, even while the Comanches celebrate their victory from higher ground. When day comes, the kid sees some outcroppings of rock about a mile away and he heads toward them.

During the day, the prisoners work in the city streets gathering up filth. Their overseer is a “goldtoothed pervert” whom Toadvine wants to kill personally. Toadvine assures the kid that they’ll get out of the prison. During the day, a cart passes in the street, led by a fat priest who is delivering sacramental bread to someone (presumably someone dying); the guards forcibly remove their prisoners’ hats as a sign of respect to the priest and his holy office.

In the gang there are two men named John Jackson, one black, the other white. They have bad blood between them. As they ride under the mountains the white Jackson pulls up next to the black and whispers to him, and the black Jackson shakes the white off. Everyone in the gang watches, but no one cautions the Jacksons to hold off in their antagonism.

Later, the scalp hunters stop at a cantina in Janos for drinks. In a dark corner, men are playing a confidence game with cards, called Monte. Out of the gloom, an old man shuffles toward Toadvine, Bathcat, and the kid. After some linguistic misunderstanding, the old man makes it clear that he welcomes the scalp hunters for fighting the Apaches; he also grieves for how much blood Mexico has shed, and suggests that war is like a dream you can’t wake up from forever. As the old man speaks, another man groans at the table of card players.

The gang doesn’t ride an hour before Apaches launch an ambush, riding across a lakebed. The scalp hunters take cover under bushes while arrows fall, and they begin to fire at their attackers, the kid calmly as though he’s done this before in a dream. After more shots are exchanged, the Apaches flee.

Some nights later, Tobin and the kid are sitting together around a campfire, the kid rather efficiently mending a strap. The two begin talking about the Judge, whom Tobin says is very gifted. The Judge even speaks, rather improbably, Dutch, which he claims to have learned from a Dutchman. Tobin spits and says he couldn’t have learned the language from ten Dutchmen; he concludes that God’s gifts are allocated very unequally. He goes on to say that the Judge is an excellent dancer and fiddler, and that he’s traveled the world.

The gang continues their journey into the mountains. At dusk, a bear rises out of the vegetation and, despite being shot by Glanton, manages to carry off in its jaws one of the Delawares. For three days the other Delawares trail the bear through the forest, but to no avail. They reunite with the gang, and between themselves the scalp hunters divvy up the dead man’s property.

For the next two weeks, the gang rides by night, making no campfires, through storms and nights of hail. At one point, they come upon five wagons aflame, surrounded by mutilated human corpses, murdered by white men who disguise their work as that of Indians. The gang uses the wagon flames to boil water for coffee and roast meat. Then they continue riding south.

In Chihuahua City, the scalp hunters go to the public baths where they strip and submerge themselves, turning the water to bloody filth. Behind them, merchants spread out European clothing and Spanish boots, from whom the scalp hunters buy many goods. The men exit into the square where the scalps they’ve taken are being hung like decorations.

The gang rides north through furious storms, rain, hail, and more rain for days on end. They ride through meadows and forests, down a mountain trail into the town of Jesús María. Glanton knocks at the door of an inn and the men are permitted to enter. By noon the next day, followed by a sad fiddler, the Americans have found a bodega run by a man named Frank Carroll and are drinking. The Judge throws a coin to the fiddler and begins to dance “with a strange precision.”

The governor of Sonora provides the gang with a new contract to hunt the Apaches. Carroll and Sanford have left the gang once and for all, but a man named Sloat has joined after falling ill and being left behind by a company of people seeking gold. The narrator implies that Sloat is not long for this world. The scalp hunters ride north onto the Sonoran Desert, where they massacre a village on the Nacozari River.

In the morning, the scalp hunters leave Santa Cruz. They ride the next day past the ruins of an estate at San Bernardino full of wild bulls, one of which gores the horse ridden by one James Miller. Miller shoots both bull and wounded horse, disgusted by the whole affair. The gang rides on.

At dusk, the gang rides out of Tucson. With them are five new recruits, Cloyce and "the idiot", and also the barrel of whiskey stolen the night before, which Glanton promised to Mangas Colorado. The barrel has been drained, refashioned, and now holds only three quarts or so of liquor. Mangas and some Apaches ride out to meet the gang, and the whiskey is exchanged for gold and silver. Mangas seems dissatisfied with the trade, but Davy Brown assures a new recruit that the Apaches won’t follow in the night.

In the early morning, Glanton, the Judge, and their five men ride out of the Yuma camp. They’ve conspired with the Indians to seize the ferry.

Glanton, the Judge, and two other gang members sit drinking tea with Doctor Lincoln, who runs the ferry on the Colorado River. Glanton warns the doctor that the Yuma Indians cannot be trusted. The Judge persuades the doctor to take precautions against an attack: to this end, Lincoln grants the gang permission to fortify the hill near the ferry, as well as to prepare the howitzer cannon he owns to be fired.

Pursued by the Yumas, Toadvine and the kid escape into the desert. The kid has taken an arrow to his leg, but keeps moving. The two spend a cold night sleeping amid the dunes, and keep moving at dawn. The kid finds a wagon tongue, which he uses as a crutch. He tells Toadvine several times to go on ahead, but Toadvine insists on staying with the kid.

Tobin tells the kid to leave him and save himself, but the kid declines and the two end up staggering onward together. When the kid notices that the wind is obliterating their footprints in the desert, he proposes to Tobin that the two of them find somewhere to hide. Tobin says that there’s no way to hide from the Judge, but nonetheless the two dig out a shelter under some mule bones and wait for the Judge to pass.

Back in town, the kid goes into a tavern where he is promptly arrested by four soldiers who don’t even ask his name. In jail, the kid speaks with strange urgency about what he has seen in his lifetime of only sixteen years, and the soldiers come to think that he has gone mad from having participated in so many “acts of blood.”

In the winter of 1878, the kid, now referred to as the man, is on the plains of North Texas. At night he sees a campfire, which belongs to an old buffalo hunter with whom the kid shares tobacco. The hunter tells about how he and others like him drove the buffalo to extinction. The hunter wonders aloud whether there are other planets like earth, or if this is the only one.

In the dawn, a man (referred to in the Characters list as the digger) progresses over the plain. He makes holes in the ground using a two-handled instrument made of steel, thereby “striking the fire out of the rock which God has put there.” Behind him, wanderers move mechanically from hole to hole, “monitored by escapement and pallet”; they seem prudent and reflective, but they are not. Their movements seem like the validation of causality. Some wanderers seek for bones; others do not. The man strikes fire in another hole and withdraws his instrument. “Then they all move on again.”