On their way to rob the train, Pike tells Dutch how he originally wounded his leg, in the third flashback of the film [the third restored scene essential to understanding Pike's motivations by depicting his possible goal of having a family life, by illustrating Pike's consistent series of miscalculations or mistakes that hurt the people closest to him in his life and caused him to feel like a repeated failure.]

He was once involved in a love affair with a woman named Aurora (Aurora Clavel) that he wanted to marry - a married woman whose husband had deserted her. Pike arrived "two days late" without explanation or apology, for a love-making rendezvous, bringing conciliatory red roses and groceries. After being slapped and told by Aurora that her husband wouldn't come back, he thoughtlessly and carelessly let down his guard, which ultimately led to the loving woman's death before a night of love-making. He was shot in the leg by the irate, vengeful returning husband of the woman he loved. When the hateful man appears, he is first reflected in the mirrored door of the dark bedroom's armoire behind her:

She had a husband. If I'd had any sense, I'd have killed him. He wasn't around. I got careless. One night, he walked in on us. Got her with the first shot. Got me here with the second. Then the damned coward turned and ran.

Although Pike didn't catch up with the cowardly killer, he admits that his guilt and the painful past still haunt him: "There isn't a day or an hour that passes that I don't think about it." Vowing to prove himself and vindicate himself in front of his comrades, Pike decides to sacrifice himself in one last job for the cause, promising:

This is our last go-around, Dutch. This time, we do it right!

The superb action scene of the train robbery begins with views of passengers aboard the train - the sleeping bounty hunters, incompetent cavalry soldiers (earlier called "green recruits, not worth a damn") and a vigilant Thornton who has anticipated their plan. When the train stops to take on water from a tower, Angel is hiding in the water chute, and the others emerge from under the tracks. Angel, Pike, Dutch, and Lyle seem to outwit Thornton by uncoupling the engine and shipment of crates of guns from the passenger car, and pulling away from the rest of the train.

Thornton, who is prepared for their scheming heist, has horses ready to pursue the engine. During the exciting chase, Angel saves Dutch from falling beneath the wheels. The bounty hunters pursue them on horseback, but are unable to catch up to the swift train. At a rendezvous point down the tracks, Tector and Sykes are waiting. The train's cargo (of grenades and rifles) is unloaded and transferred onto a wagon and hauled away. Pike then reverses the train's engine, and sends the hijacked front portion of the train speeding back toward Thornton and into the stranded cars on the track.

Anticipating the bounty hunters' and cavalry chase, Pike sets dynamite to explode the main bridge across the Rio Grande River on the border between the U.S. and Mexico. Before the dynamite detonates, Pike removes his hat and gallantly but defiantly gestures toward Thornton in a magnificent salute. The explosion is so violent that Pike and his horse both flinch convincingly when the charges blast. When the bridge collapses and Thornton's half-a-dozen men and horses plunge into the water, the long-lens prolonged, slow-motion images are aesthetically and expressively violent.

Due to the success of their getaway, Pike is restored to his esteemed place of leadership by the gang, and the outlaws share a drink from a common whiskey bottle while on horseback. They burst out in laughter when an empty bottle reaches Lyle. They know that Thornton has only been temporarily delayed, as Sykes reminds them: "He'll be along..."

Just before Pike and the gang deliver their load of guns, General Mapache's forces, lacking the stolen guns to protect themselves, are surrounded and beseiged at the Las Trancas train station by Pancho Villa's revolutionary troops. The general's forces have temporarily left Agua Verde and taken a train there to retrieve a telegram message from the Bunch about their looting of the US munitions train. Mapache nervously stands his ground defenseless on the train tracks, as shells explode around him. He fearlessly refuses to scurry for cover, acting heroically for a young, wide-eyed telegram delivery boy (dressed in military clothing) who stands nearby, salutes, and admires his newfound hero's courage. The delivered telegram informs Mapache that the train has been successfully assaulted and Pike has acquired the arms shipment ("the gringos assaulted the train, they got the guns"). The boy salutes the general, and they walk calmly together toward the train as the scene ends.

Meanwhile, Thornton is ashamed of his small force of men, and condemns his inept bounty hunters. He wishes that he was with Pike instead:

And what do I have? Nothin' but you egg-suckin', chicken-stealing gutter trash, with not even sixty rounds between you. We're after men, and I wish to God I was with them. The next time you make a mistake, I'm gonna ride off and let you die.

And Pike suspects that Mapache may double-cross them when they meet near Agua Verde to exchange the guns for gold:

I figure that damn General will try to take this load without payin' for it and shoot us in the bargain. Only thing that'll change his mind is if somethin' would happen to these guns.

The gang finds a belt-fed Maxim machine gun in the haul, and Pike wants to learn about the new advanced weaponry:

What I don't know about I sure as hell am gonna learn.

Angel's revolutionary followers surreptitiously surround them in their rocky hideout and leave with a case of guns, fulfilling Pike's earlier bargain with Angel. The villagers could have taken the entire wagonload of munitions if they had wanted. Pike knows their potential with the proper leadership:

If they ever get armed with good leaders, this whole country will go up in smoke.

A little later, a concerned Mapache watches empathically as his bloody, wounded men are treated following their struggle with Villa's forces. He is reminded: "With the new guns and ammunition, this would never have happened."

In a tense standoff when they meet to trade with Mapache, the Bunch is cornered and trapped by Mapache's followers lined on the tops of steep canyon walls, led by Herrera (Alfonso Arau). Pike forestalls their intentions to claim the arms without making payment, by threatening to touch a lighted cigar to a fuse attached to sticks of dynamite to blow everyone up:

Pike: Any trouble, no guns for the General.
Herrera: Ha, ha, ha. Very smart. That's very smart for you, damn gringos. So nobody can rob the guns.
Pike: Nobody.
Herrera: I am not afraid. They are not afraid. You blow up the wagon, you die. Or we kill you pretty soon. But we are amigos.
Dutch: Show 'em boys.

Tector and Lyle pull off a cover to reveal the awesome machine gun; a shot is fired by one of the Mexican gunmen, and Pike immediately lights the fuse to show that he means business. As it sizzles in his hand, Herrera begs Pike: "Please, cut the fuse!" The trigger-happy gunman is shot and killed by his own troops, punished for endangering the safe delivery of the rifles. On his own terms, Pike tells Herrera that they will trade the guns the following day with the General in a rendezvous at Agua Verde.

As agreed, Pike rides into the General's fortress to trade the guns for money, but to prevent a possible double cross and ensure payment, he will exchange guns for gold only in gradual allotments. Pike brings in information about the first shipment of four cases to Agua Verde, in exchange for $2,500:

When I get my share of the gold, twenty five hundred dollars worth, I'll tell you where four cases are. The others are waiting for me back at the wagon. If I don't show up pretty quick, they'll blow it...The quicker I get back, the quicker you get the next load...Up the arroyo about two miles, you'll find three cases of rifles and one case of ammunition hidden in the bush.

To inspire good will, Pike promises the General that although the machine gun was not part of the original transaction for 16 cases, it will be presented to him. As Pike rides away, the General beams: "I trust him."

The Gorch brothers are chosen for the next exchange of cases, along with the machine gun, followed by Dutch and Angel for the final exchanges. After the gun has been presented to Mapache, his men fire it with no knowledge of how it works. In the comic scene, people duck for cover and pottery is shattered, as the wildly-aimed gun shoots up the entire compound. When it is thought that the gun is finally silenced, Mapache holds it in his arms - and it starts firing again, blasting hundreds of rounds of bullets.

In the final exchange of information about the location of the remaining cases, Dutch and Angel ride in to collect their share of the loot, but Mapache knows of Angel's deceit and betrayal - that he has diverted one case of the stolen guns to arm Mexican revolutionaries. Dutch's coverup isn't convincing: "(There were) sixteen cases of rifles. We lost one on the trail." It is learned that the grief-stricken mother of the young Mexican's girlfriend betrayed him to Mapache (Lyle later characterizes it this way: "Her own mama turned him in like some kind of a Judas") to find justice for her daughter's murder. Sensing the danger he is in, Angel attempts to ride to freedom, but is seized and brought before the chieftain. Outnumbered and outgunned by Mapache's forces, Dutch is torn between his own safety and loyalty. He decides to claim that Angel is indeed a thief, abandoning him: "He's a thief. You take care of him."

Now that Mapache is supplied with guns for his 200 men, returning to rescue the young gang member would be suicidal, as Pike summarizes: "No way at all." While Sykes is riding to rendezvous with the rest of the Wild Bunch with pack horses, the gang watches as Thornton's bounty hunters open fire and Sykes is seriously wounded in the leg by Coffer. Dutch is angered:

Dutch: Damn that Deke Thornton to Hell!
Pike: What would you do in his place? He gave his word.
Dutch: Gave his word to a railroad.
Pike: It's his word!
Dutch: That ain't what counts. It's who you give it to!

Running short of water and "tired of being hunted," Pike decides to go back to Agua Verde and seek refuge there with Mapache's protection:

Pike: Let the General take care of those boys [the bounty hunters].
Lyle: You're crazy. That General would just soon kill us as break wind.
Pike: He's so tickled with those guns, he'll be celebratin' for a week and happy to do us a favor. Thornton's not gonna follow us in there. While they're busy pickin' over Freddy (Sykes), we'll find a back trail off this mountain and head for town.
Dutch: What about our gold?
Pike: We'll take one sack to pay our way. Bury the rest - together.

After the wounded Sykes [shot in the right thigh, but later seen with a bandage on his left thigh] has been pursued into the hills by the bounty hunters, and thereafter approached from behind by a Mexican revolutionary with a machete, Pike and the four remaining members of the Gang ride back into the General's compound at Agua Verde. A loud fireworks celebration is in progress. In a drunken display of debauchery, Mapache crudely drinks in his open carful of whoring women as it drives in circles, dragging Angel in the dust from a rope tied to the rear fender. Children gleefully shout and run after Angel's body as it is pulled around in the dirt by the car. Pike and Dutch are both appalled by the new invention, used for torture:

Pike: God, I hate to see that!
Dutch: No more than I do.

Pike demands Angel's release in exchange for half of his robbery take/share: "I want to buy him back." Mapache refuses (he claims that he doesn't need gold), and Lt. Zamorra invites them to join the joyous party instead - with whores and whiskey: "Why don't you go and get a drink, enjoy yourself, there are women everywhere?" While Pike responds, "Why not?", Dutch mutters, "son of a bitch," as his commentary upon Angel's torture. [This is one of many instances of the use of language that demystifies and shatters the ideal of the romanticized West within the film.] While the men seek solace in the company of young Mexican whores and ignore Angel's plight, a disheartened and concerned Dutch waits outside and whittles on a piece of wood (possibly remembering how Angel saved his life on the train).

Meanwhile, Pike enjoys the company of a young woman, whose crying baby on the dirt floor reminds him of the family he might have once had with Aurora [and reminds him also how he acted wrongly in her defense]. While dressing in the adobe room, he watches as the beautiful young woman delicately cleanses her upper chest with water from a basin. When he offers her payment, she expresses humiliation or disappointment, causing Pike to experience troubling, remorseful second thoughts about being oblivious to one of the Bunch. After finishing the remains of a whiskey bottle, Pike makes a silent decision - to rescue their Mexican partner and Bunch 'family' member - Angel. [Throughout his past, Pike had abandoned or betrayed his partners by not sticking with them (e.g., Crazy Lee, Buck, Angel, Sykes, and Deke), but now, he acts otherwise.]

The two Gorch brothers argue with another of the whores regarding her payment price, claiming they earlier bargained a two-for-one deal. Shortly afterwards, a steely-eyed and determined Pike enters their room and summons the men to help their Mexican comrade Angel, in one final act of redemption, without any explanation:

Pike: (flatly) Let's go.
Lyle: Why not!?

As they leave, a tiny sparrow tethered to a string [the string recalls the rope that tied Angel behind the automobile] that Tector was idly playing with, lies panting and dying on the ground - a foreshadowing of the fate of the Bunch. Encouraged by their unspoken, heroic, and courageous decision to arm themselves and save one of their own, Dutch joins his comrades. Pike's victory in his final robbery heist cannot be savored - he must lead his group to uphold its honor, to live up to its pronouncements on solidarity, to commit itself to a futile but necessary action, and to nobly sacrifice itself for the persecuted and captive Angel in a final showdown.

The four load their rifles and march across town - four abreast, reminiscent of the walk to the classic O.K. Corral in other westerns - to confront the drunken Mapache, who holds court next to the machine gun, his proud possession mounted on a table. Pike demands the return of Angel ("We want Angel"), now bloodied, maimed and near-death from torture. Mapache appears to comply, assisting Angel's walk over to them and then cutting his wrist ties with a knife. But in a brutal, full-frontal view, Mapache slits Angel's throat and is immediately killed in retribution by Pike and then by Dutch and Lyle.

The precipitation of their last stand - a violent, seven minute bloodbath counter-attack of monumental proportions in the open courtyard - is delayed with a long moment of silence. With their guns drawn, the four men are able to hold off hundreds of surprised and dumbstruck Mexicans, which now stand leaderless and still for several seconds, gaping at what has happened. Warily and then gleefully, Pike and Dutch smile and laugh, realizing that for an instant, they just might succeed. Pike whirls around - not a single soldier moves. However, they are outnumbered, surrounded, and condemned to die in the pending climactic battle. [Other classic last stands in westerns include The Magnificent Seven (1960) and The Professionals (1966).]

Choosing his next target deliberately, Pike fires on Mapache's German advisor Mohr and kills him with a single, well-placed shot - and then Mapache's two seconds-in-command (Herrera and Zamorra) are shot, followed by Mohr's aide. The real, pitched battle in the fortress then begins in one of the most complex, highly-edited sequences ever filmed. It is truly an orgy of slaughter in one of the bloodiest scenes ever filmed, as the four remaining outlaws take down as many men as they can. Although some of the Wild Bunch hold off the troops momentarily by using grenades and by commandering the machine gun [the ultimate symbol of the new industrial society] and firing it with orgasmic intensity, they are soon wounded - first Tector and then Lyle (both at the machine gun) fighting side by side, then Dutch, and finally Pike. Dutch takes cover behind one of the prostitutes, using her as a shield.

Trying to find cover, Pike backs into a room where a woman appears reflected in a mirrored door of her wardrobe. He fires at the reflection, killing a half-clad officer hiding behind the door. He turns away from the Mexican whore, who leers at him and suddenly shoots him in the back. He reflexively turns and fires directly into the chest of the woman, crying out: "Bitch!" [The use of this expletive was unusual in a western. For Pike, elements in the scene brought back the thought of the earlier scene of Aurora's death in her bedroom.] The two brothers are the first to be killed. Pike then takes charge of the machine gun, blowing up boxes of grenades and explosives to decimate even more of Mapache's army. A young child in an ill-fitting army uniform fires the first of many fatal shots into Pike's back at point blank range. He dies still clutching the gun's trigger with its nose pointed upward, with Dutch calling out to him and falling by his side to join him in death. In their violent deaths, they have become liberated.

Images of death and slain bodies surround the compound - vultures sit in anticipation on the town's walls, and peasant women in black mourn the fallen where the wounded still move among the dead. Now that the General's army is no longer a threat, Thornton and his men ride into the town to take stock of the slaughter. The vile, 'vulturish' bounty hunters scurry around, picking over the bodies (searching for boots, gold fillings, and watches), as Thornton sadly finds the corpse of his once closest friend and mourns his death. Eyeing Pike's Colt .45 pistol still in its holster (unused), Thornton claims it for himself - paying homage to the bygone past by inheriting the talismanic object. The scurvy bounty hunters claim responsibility for Pike's death:

Look at it. We got 'em all. Do you see? There he is. There's Pike. You ain't so damn much now, are you, Mr. Pike?

After slinging the bodies of the dead men in the gang over their saddles (as Harrigan wanted), the bounty hunters find Thornton sitting in the blowing dust at the wall (outer gate) of the town, electing to stay and not return to the U.S. with them. Exhausted, he feels that his debt to Harrigan has been paid. The other remaining Mexican survivors of the battle slowly file out of the town with what they can carry. In the distance, Thornton knowingly smiles when he hears the echoes of death in the whistling wind - the revolutionary rebels (or the cavalry that had earlier fired upon the bounty hunters at the bridge) have probably executed the worthless bounty hunters. A few moments later, a rescued Sykes rides up with the revolutionaries and elder Don Jose from the village - they find Thornton still sitting by the wall. Sykes confirms the fate of the bounty hunters and then asks if Thornton wishes to search for new adventures:

Sykes: I didn't expect to find you here.
Thornton: Why not? I sent 'em back; that's all I said I'd do.
Sykes: They didn't get very far.
Thornton: I figured.
Sykes: What are your plans?
Thornton: Drift around down here. Try to stay out of jail.
Sykes: Well, me and the boys here, we got some work to do. You wanna come along? It ain't like it used to be, but, uh, it'll do.

They both laugh - they and the revolutionary Mexican peasants are rid of their oppressors. Thornton mounts his horse and decides to ride off with them and join in the Mexican Revolution, thereby forming a 'new' Wild Bunch with Sykes, one of its original members. Former 'reincarnated' images of the members of the old Wild Bunch, when they would sit around together (and engage in laughter - linking them to Sykes and Thornton), and when they rode away from Angel's village, flash momentarily onto the screen as the end credits roll up (accompanied by a reprised chorus of La Golondrina).