Passing through a town, a farm boy aspiring to be a bounty hunter rescues a woman who has been tricked into working in its brothel and the two travel towards his father's ranch.
After his girlfriend dies in childbirth, Confederate deserter John Warner travels to Mexico, where the woman's father, Don Pedro Sandoval, grudgingly hands over his child. But with no locals willing to provide milk, the baby dies. Rounding up a group of rebels, Warner goes on a rampage through northern Mexico, with the ultimate goal of taking down Sandoval in this gritty Western.
When Quintero, a Mexican revolutionary leader, is left to rot in jail by the forces of President Diaz, it's up to his subordinate, Max, to bust him out. With $600 in hand, he crosses the border into America and hires Chris Adams, a mercenary of considerable skill, who uses the rest of the cash on more hired guns. After the team is rounded out by experts on close-combat fighting, explosives, and knife-throwing, they set off to free Quintero.
Don Juan, the governor of a Mexican province, arrests Manuel, the fiancé of the beautiful heiress, Virginia. When Quintana frees Manuel, Don Juan kidnaps Virginia to force her hand in marriage. The ceremony is interrupted in a violent battle.
Renegade Confederate soldiers take over a frontier town, but after they molest a young black woman, a group of ex-slaves arm themselves and counter-attack.
A widow hires an ex-gambler to retrieve gold bars from a sunken river boat in Colorado and discreetly return them to the Federal Mint, from where they had been stolen by her dead husband.
Photographed by famed cinematographer Laszlo Kovacs just before embarking on EASY RIDER (1969), Mark of the Gun is a classic western tale of outlaws and the women they love.
When the multiple murderer Cain is released from prison after 18 years, he wants to settle down as a rancher and never touch a gun again. But his former life haunts him; not only that nobody wants to give him a job, some villains also want to pay him back. So he has to accept the offer of showman Ruffalo to perform as "Killer Cain" in his traveling shooting show. However after 18 years without practice even Ruffalo's young assistant Billy shoots better than Cain.
During the American Civil War, a Confederate prisoner, Clyde McKay, attempts to steal a box of gold from a Union prison camp. He is aided by a group of prisoners and a prison guard but he is double-crossed along the way.
While a Mexican revolutionary lies low as a U.S. rodeo clown, the cynical Polish mercenary who tutored the idealistic peasant tells how he and a dedicated female radical fought for the soul of the guerrilla general Paco, as Mexicans threw off repressive government and all-powerful landowners in the 1910s. Tracked by the vengeful Curly, Paco liberates villages, but is tempted by social banditry's treasures, which Kowalski revels in.
Three men meet in the same prison and in their cell they find a Mexican boy condemned to death for murder. One night the three convicts are mysteriously released by a priest and the father of the Mexican boy who promises them a reward of $30,000 if they can find the real murderer within ten days. Certain that the Mexican boy is not guilty, Reno and the others organize a plan which leads to the unmasking of the real killers.
Bespectacled pistolero Stan Ross comes to Canyon City and becomes involved with two feuding factions, after a clerk has been killed by the banker Jefferson during a botched holdup, while robbing his own bank.
Two men are on their way to Denver City to settle a personal score. One is looking for the murderer of his father, the other for a former friend who stole his gold. They're joined by a third person, a mysterious pistolero.