In 1879, members of the outlaw gang known as the Cochise County Cowboys, led by William Brocius, ride into a Mexican town and interrupt a local police officer's wedding. They then proceed to massacre the assembled policemen in retribution for killing two of their fellow gang members. Shortly before being shot, a local priest warns them that their acts of murder and savagery will be avenged, referencing the biblical Four Horsemen of the Apocalypse.