First Flashback:

In the first flashback at an Indian agency, Martin is pictured bartering two blue silk rosettes (marked LARD Type Hog) and hats with a plump Indian woman (and her father), in exchange for a blanket. Unwittingly, he acquires a chubby and homely Indian bride. Thinking they are a week away from catching up to Scar's hostile band, Ethan leads Marty away from his trading session. They are soon followed by Marty's new Indian bride (Beulah Archuletta) on horseback, whom he accidentally purchased - she sports a derby hat. Shadowed by the new Indian wife, Ethan laughingly explains Marty's misunderstanding to further humiliate him:

You don't understand, you chunkhead. You didn't buy any blanket. You bought her. You've got yourself a wife, sonny. Ha, ha, ha.

Ethan jokes with the new squaw about her 'marriage': "Come on, Mrs. Pawley. Join our merry group." [Martin's marriage to the Indian woman is the comical obverse of white girl Debbie's miscegenation with Indian chief Scar. In the former case, Ethan is amused by the unattractive Indian maiden now married to a white man; in the latter, Ethan is filled with loathing.]

Laurie continues to read the letter from Marty:

There is one other thing I got to tell you before you hear it from Ethan - how I got myself a wife...(Overjoyed and opportunistic, Charlie, with a parody of a Texas accent, guffaws at the news: "He did?...Hawh! Hawh! Hawh! Hawh! Hawh!") A little Comanche squaw...

She has read enough, and she is also not amused by her father's reaction: "A young man should get married early in life. Right, Mama?" Fuming and feeling insulted, Laurie cries out "Squaw!", crumples the letter and throws it into the mantleplace fire, but her father rescues and retrieves the partially-burned pages. After she is scolded, Laurie is forced to resume her reading, while Charlie rubs it in even further: "So he married a Comanche squaw. Hawh! Hawh! Hawh!":

She wasn't near as old as you. (To herself) How old does he think I am?!

Second Flashback:

In a second flashback, Martin's new squaw serves them coffee, and mistakenly receives the name "Look" after he tells her: "Oh, Look, I sure do wish I could make you understand. Oh." Ethan interprets her Comanche words about her fancy name: "She says her name is Wild Goose, Flying in the Night Sky. But she'll answer to 'Look' if that pleases ya." That night, as Look dutifully lies down next to Marty, he maddenedly kicks her off his bedroll and down the hill where they are camped, causing a racist Ethan to give a horse-laugh and react: "You know that's grounds for di-vorce in Texas! You're really rough." Ethan and Marty both hold Look by each arm and ask her about Chief Scar, causing a look of terror in her face: "Do you know where he went? Did he have a girl with him? A white girl?" During the night, Look runs away, leaving directional markers on the ground with an arrow of rocks.

The film's flashback returns to voice narration, mixing Martin's voice-over into Laurie's voice. The two men come upon a buffalo herd in the snow:

Maybe she left other signs for us to follow - but we'll never know cause it snowed that day and all the next week. We're headin' north through buffalo country when somethin' happened that I ain't got straight in my own mind yet. And on this day, we sighted a small herd. Say we needed some meat so we circled around and come up on 'em on foot.

Third Flashback:

In a third flashback, Martin and Ethan approach a snow-covered area where buffalo are gathered. Ethan shoots one of the buffalo, causing the rest to stampede. Then he goes into a passionate frenzy, shooting wildly at the herd - his senseless slaughter of the buffalo is intended to starve and deprive the Indians of food. Marty protests the deliberate killings to deny food to the Indians but Ethan doesn't listen: "At least they won't feed any Comanches this winter." [His tactic suggests the same paradoxical approach toward Debbie - kill his own kin to cleanse her. Ethan's rampage against the buffalo parallels Scar's killing of cattle to lure the white men away from the ranch.]

Bugle sounds of a cavalry troop in the distance are heard merging with Ethan's gunshots, as they sight the renowned Seventh Cavalry, photographed majestically. As a jaunty Irish jig Garry Owen plays on the soundtrack, the cavalry is viewed in a mythically glorious sequence - they ride beautiful horses in lines, gallop through an icy river, and carry colorful flags against the white of the snow. Ethan and Marty ride up into an Indian camp/village, a scene of more slaughter - bloody corpses lie everywhere on the snowy ground, the result of a cavalry massacre, and a return to the cycle of retributive slaughter of one race by another. [The aftermath of the ride of the clean-cut cavalrymen is the bloody massacre of Indian women and children.]

In voice over during the flashback, Marty describes the scene:

It was Nawyecka Comanches all right, the ones we'd been lookin' for all this time.

In a tepee, Ethan finds Look's body among the dead, covers her with a blanket and rubs snow from her derby hat. Martin is disturbed by the sight of her body and her cruel and senseless death at the hands of US soldiers. [The feelings engendered in Marty equal what would be felt if Ethan killed Debbie.] He is remorseful but not vindictive:

Marty: What did them soldiers have to go and kill her for, Ethan? She never done nobody any harm. We gotta catch up with them yellowlegs. Maybe they've got Debbie with 'em.
Ethan: Maybe they've got that chief they call Scar.

Marty continues the voice-over in the third flashback, giving Look the benefit of the doubt regarding whether she was killed trying to warn the Nawyecka or to find Debbie for him:

So we figured Debbie had been in the village. What Look was doin' there, whether she'd come to warn 'em or maybe to find Debbie for me, there's no way of knowin'.

The Seventh Cavalry herds captives into a fort, and Ethan and Martin inquire about inspecting the white captives rescued from the Comanches. In the fort's chapel, they find one half-crazy young white woman moaning to her doll, driven mad by her years among the Indians. When they approach, the crazed girl makes a lunatic howl. Two other young girls hang on to each other, both insane and with a wild look on their faces. In another of the few close-ups in the film, Ethan reacts with revulsion toward the broken human beings and their insane ramblings, staring toward the one terrified girl crooning to Debbie's rag doll:

Sergeant: It's hard to believe they're white.
Ethan: They ain't white any more. They're Comanche. Where are your casualties?

None of the survivors or casualties are identified as Debbie. Ethan's hard-driven, ultimately five-year mission to find Debbie becomes a combination of self-discovery, revenge in the name of Martha's death, racist hatred and intolerance, use of survivalist techniques and knowledge of the ways of the Indians, and now homicidal rage.

Laurie sorrowfully concludes the third flashback with the final part of the letter, disconsolately putting it down in her lap when she finds no words of encouragement or love from Martin:

So we're setting out for New Mexico Territory in the morning. I am sorry I won't be back for Christmas again this year. I set pencil aside in the hope you are enjoying good health and your folks the same. I remain respectfully, yours truly, Martin Pawley.

Lars Jorgensen feels the searchers will never find Debbie after years of endless pursuit. He takes the letter from Laurie's lap, folds it and puts it in his pocket, and then walks out smoking his pipe. Laurie is distraught: "'Yours truly.' Ma, he had to sign his whole name, Martin Pawley, he couldn't write just 'Marty'. I don't care if he never comes back." As Laurie bereftly stares out the front door at the sunset, lonely and thinking of Martin, Charlie casually strolls up behind her, strumming his guitar and singing: "Gone again, skip to my Lou, Gone again, skip to my Lou, Gone again, skip to my Lou, Skip to my Lou, my darling." As she turns to him, the scene dissolves to a long-shot view of Ethan and Martin riding along a ridge in front of an orangish-brown sunset. Laurie will soon decide to choose as Martha did - to marry another man for comfort and not wait interminably for a wanderer's return.

After the extended flashback sequence concludes, the searchers follow Scar's trail into the New Mexico territory (or somewhere south of the border). At a cantina about three years later (now five years since the start of the search), they are both found wearing straw hats and checked shirts (and the horse hitched out front is sporting a sombrero). Inside, they encounter old friend Mose Harper, who has also been looking for Debbie and has accidentally found her trail:

Mose: Been helpin' ya, Ethan, been lookin' all the time.
Ethan: Well, the reward still stands.
Mose: Don't want no money, Ethan. No money, Marty. Just a roof over ol' Mose's head, and a rockin' chair by the fire. My own rockin' chair by the fire, Marty.
Ethan: You help us find that girl, you've got your rockin' chair.

Ol' Mose has located a man who has seen "little Deborah," - a dignified-looking, white-bearded Mexican in the cantina named Emilio Gabriel Fernandez y Figueroa (Antonio Moreno), wearing a maroon-colored velvet jacket, a wide sombrero, and jangling spurs on his boots. Figueroa overhears their conversation and offers to provide information "for a price." Behind him, a costumed Mexican dancer in a red dress twirls and shakes her castanets until ordered to cease. Ethan tosses a bag of gold coins on the bar, asserting: "Let's talk a little business," much of which is conducted in Spanish. Marty is entertained by the friendly dancer as he wolfs down a traditional meal of beans ("mas frijoles") and tortillas. After Ethan learns the whereabouts of Chief Scar, he promptly announces their next step - a meeting with a Comanch named Cicatriz: "Cicatriz is Mexican for Scar." As he says Scar's name, he heaves Marty's tequila drink on the fire - and it flares up to accentuate the volatility.

Ethan and Martin (posing as traders) are led to Scar's camp in the desert (again Monument Valley) at the head of a long line of Mexican horse riders:

Ethan: Medicine country, huh?
Figueroa: Bad medicine, I think.

When Chief Scar first emerges from his tepee and sees Ethan, they stare each other down, only inches from each other's faces - appearing as reflective mirror images of each other. [The scene was shot to deliberately emphasize their resemblances.] They greet each other with ritualistic, macho bravado - trading insults:

Ethan: Scar, eh? It's plain to see how ya got your name.
Scar: You, Big Shoulders. (Then, pointing to Marty) The young one - He-Who-Follows. [Scar's name for Martin.]
Ethan: You speak pretty good American, for a Comanch. (Did) someone teach ya?...
Scar: (echoing Ethan's words) You speak good Comanch. (Did) someone teach you?

When they enter the tepee to trade and escape the wind, Figueroa points out Scar's wives - four women at the rear of the teepee. He explains how Scar's own two sons were massacred by whites. [Both Ethan and Scar are victims of savage acts of retribution, emphasizing the similarities in their motives for revenge. Scar surrounds himself with trophies of his hate, acquired during his revenge for sons killed by the white man. Similarly, Ethan wants revenge on Scar because Martha, Aaron, and most of the Edwards family are also dead.] For each dead son, Scar vengefully took a scalp:

Figueroa: His sons are dead, so his wives sit on the other side of his lodge.
Ethan: Are all those his wives?
Scar: Two sons killed by white men. For each son, I take many (He looks to Figueroa to provide the white man's word)...scalps.

Scar has one of his wives get up to hold and display in front of them a lance from which hangs a collection of many whites' scalps. As Ethan and Martin look at the grisly trophies, they glance up to their right to see an older, teenaged Debbie (played now by Natalie Wood, Lana Wood's elder sister), an Indian squaw of renegade Chief Scar (the assassin of Debbie's mother) dressed in full Indian costuming (a light-brown velvet blouse held by a silver conch belt, and a purple skirt), with braided hair and a beaded Indian necklace. Ethan is shown the medal he once gave Debbie, now dangling around Chief Scar's neck, but Ethan refuses to be taunted and leaves the tepee, insisting on trading with Scar the next day on the other side of the creek: "I came to trade, not to admire his collection."

Later, Figueroa tells the vengeful Ethan his fears of what may happen in their next confrontation. Realizing that Scar knows who the searchers are, Emilio wants no part of the "blood money":

Figueroa: But he knows who you are, and why you're here. This, I did not know. (He hands back the bag of gold.) Take it. I do not want blood money.