Seven American gunmen hire themselves out to protect a Mexican village from bandits.

When ruthless bandit leader Calvera and his forty men raid the Mexican village of Ixcatlan for food and goods, the villagers, used to Calvera's harvest-time plundering, keep quiet with the exception of one outraged farmer, whom Calvera summarily shoots. After the banditos leave, the villagers, barely able to survive on what remains but unable to fight the banditos, seek the advice of the old man, a village elder, who tells them to buys guns at the border and learn how to use them. When the three-man delegation from Ixcatlan led by Hilario arrives at a border town to buy guns, they are awed by gunslingers Chris and Vin, who offer to drive a carriage carrying the body of an Indian through town when the funeral director refuses to transport it for fear of the bigoted citizens' reprisals. After witnessing Chris and Vin easily outdraw the angered townsmen as they make their way to the graveyard, the delegation asks Chris to buy guns for them, explaining that the Mexican rurales cannot guard the village from Calvera's repeated plundering. Chris instead offers to round up a team of gunmen, even though the villagers can only afford to pay $20 pay for six weeks' work. As word spreads, young, impetuous Chico, inspired by Vin and Chris's triumphant carriage ride, asks for the job, but is humiliated when he fails Chris's test to determine if Chico is a quick draw. Soon after, jovial gold hunter Harry Luck, assuming that there must be some hidden treasure which the other gunslingers will split, joins the team, as well as Vin and the brawny war veteran O'Reilly. The next day, Chris watches as expert knife-thrower and gunslinger Britt easily wins a draw with a deadly knife throw and considers him for the team. At a bar that night, an enraged Chico holds Chris at gunpoint and orders him to draw, but Chris quietly refuses the challenge until the boy collapses from drunkenness. Soon after Britt joins the group, the well-dressed but destitute Lee offers his services in attempt to regain his nerve, which he has lost while on the run from his enemies. Days later, as the delegation, joined by the six gunslingers, rides toward Ixcatlan, they notice Chico following and Chris, softened by the young man's resolve, finally motions for him to join them. When they are greeted with silence as they enter the village, Chris accepts the villagers' fearful reluctance, but Chico angrily rages at them for their cowardice. The next day, the seven attend a town celebration and notice that all the village women are missing. Soon after, Chris learns that three of Calvera's men are nearby and sends Britt and Lee to bring the men back alive. However, Chico ruins the plan by shooting one of the banditos, forcing Britt to kill the second and third men, who were fast escaping on horseback. When an amazed Chico compliments him on his long-distance shot, an irritated Britt tells him that it was "the worst. I was aiming for the horse." Later at the village, Chris observes that Calvera probably sent the men ahead to scout for the coming raid and reassures the villagers that they will have time to train before Calvera's men arrive in force. Over several days, the seven use the dead men's weapons to coach the farmers in how to shoot. One afternoon, Chico catches the strident young Petra, who is spying on him as he tests his bullfighting skills against a tame farm animal, and learns that the villagers have hidden their women for fear of the gunslingers raping them. After warning the village men that the women have more to fear from Calvera than from the gunslingers, Chris orders Chico to bring the women back. That night Petra and others petulantly serve the men food, but when the seven learn the village is starving on a few meager beans, they give their servings away. The next day, after the boys on guard signal that the enemy is approaching, Chris, Britt and Vin stand in the middle of town to meet Calvera, who does not flinch at finding gunslingers there. Instead, he offers to share the village spoils with the seven in exchange for standing down, but when Chris orders him to "ride on," a gunfight erupts. Unprepared for the onslaught, Calvera and his men try to escape but are trapped by newly built nets and rock walls erected by the villagers, thus enabling the villagers and gunslingers to pick off many of the banditos. That night, as the mild-mannered Sotero and other villagers toast the seven on their success, shots interrupt the jubilant occasion, forcing Chris to send O'Reilly, Vin and Sotero to track the sharpshooters. While searching for the men, Sotero tells Vin that he is committed to protecting his family, and Vin openly envies Sotero's bond with his family, which neither he nor the other six have. Meanwhile, disobeying her father's orders against talking to the gunslingers, a love-struck Petra begs Chico to be careful. Later that night, Chico, wanting to prove himself to the others, touts the gunslinger lifestyle as the stuff of legends. While Chris reminds them, as hired gunmen, they are beholden to no one, Vin laments that he has no family and Lee adds that they have no enemies, because they are dead. When Lee awakens screaming from a nightmare about his enemies, two villagers reassure him that "only the dead are without fear." Meanwhile, three young boys adopt the Mexican-Irish O'Reilly, promising that they will avenge his death and put flowers on his grave if he should die in battle. Harry is convinced that the villagers must be hiding ancient treasure, which is rumored to be buried in the nearby mountains. Believing that this is the real reason for Calvera's return, Harry tries to entreat the village men into gambling. Meanwhile, Chico, hiding his face under a sombrero, infiltrates the Calvera camp and surprises the six when he reports back that Calvera will attack soon because his men are starving. The villagers fight among themselves about whether to surrender to save their families, while Chris argues with his men about their chance of success. Later, Chico boasts to Petra about his new life as a roving gunslinger, but his resolve quickly weakens as she kisses him. That evening, after Chris and his men find the Calvera camp empty when they attempt to steal their horses, the seven return to the village and are immediately surrounded by Calvera's men, who have been tipped off by the cowardly Sotero. Although he could easily kill them, Calvera decides to spare their lives to avoid alerting the United States police to his operation. After publicly ordering them to leave their guns, Calvera quietly offers to return the weapons once the seven are out of town and asks why they became involved with the villagers, unable to believe the gunslingers would have any motivation other than money. As he lays down his gun, Vin cryptically explains with a joke: When someone asked a man why he threw himself into a prickly pear cactus, the man simply replied that it "seemed to be a good idea at the time." Before the seven leave, O'Reilly explains to his boys that they should respect their fathers, who are brave to carry the burden of family responsibility, something O'Reilly has never had the courage to do. That night, after the seven are escorted out of town and given their guns, Chico explodes in anger about the villagers' betrayal, but Chris reminds him that his hatred stems from being the son of just such a Mexican villager. The next day, after Harry, tired of fighting without the hope of riches, leaves the group, the remaining six ride into town and begin a shootout with the banditos. Wounded, Vin drags himself into a store, while Harry, having changed his mind, rides into town and is shot. Following Vin, Chris drags Harry into the store, where he soothes the dying man with a story of imaginary riches. Meanwhile, Lee finally draws and shoots four of Calvera's men, but is then killed. Spurred by the seven's sacrifice, the villagers, including the women, come out of hiding and beat Calvera's men with every chair and stick available. Meanwhile, Chris wounds Calvera, who, with his dying breath, continues to express his disbelief that the seven had any reason to return. After Britt takes out four banditos with perfectly aimed shots, he dies from a wound sustained in the battle. O'Reilly's boys find their hero, who begs them to emulate their fathers, then dies from a wound suffered before their young eyes. By the end of the battle, the remaining banditos are finally driven from town, but the old man sagely announces to those remaining of the seven, Chris, Vin and Chico, that only the farmers have won. As they ride out of town, the astute Chris turns to Chico, tells him "adios" and watches as Chico returns to Petra, for whom he lays down his holster. As they pause to look back on the village, Chris tells Vin that the old man was right, only the farmers have won, not the gunslingers, who will always lose.