Jim Hardie hunts for an outlaw who killed a Wells Fargo employee, but the killer is also being sought by two Apaches for killing a woman and her son.
Hardie is stuck in Mesa City, where there isn't a sheriff.
On orders from Territorial Governor Gosper Wyatt Earp heads south to make peace when he learns that Old Man Clanton has sent his men into Mexico to rob the silver trains and steal the cattle of wealthy Mexican rancher Don Sebastian.
Wyatt arrests and jails the McLowery brothers for mail robbery. Soon afterwards, however, he is enraged to learn that, because the McLowerys work for Old Man Clanton, they've been released by Sheriff Behan, who's on Clanton's payroll.
A stagecoach holdup orchestrated by Johnny Ringo and Curly Bill Brocius gives Wyatt Earp the opportunity he's been waiting for--a chance to get the rival factions in the Clanton gang to turn on each other instead of the law.