The Good Guys and the Bad Guys (1969)

Jim Flagg is the marshal in the town of Progress. He hears arch-rival John McKay is headed toward town so he warns Mayor Wilker and others in Progress that there's sure to be a robbery. Wilker doesn't appreciate Flagg causing a panic and relieves him of his badge.

Flagg sets out on his own. He discovers McKay has joined up with a band of youthful outlaws. Taken prisoner, Flagg escapes death thanks to McKay's intervention, but the two old enemies end up in a bloody fistfight.

Taken back to town, Flagg puts McKay in a boarding house run by Mary, a widow. When the outlaws arrive, intent on robbing a train, McKay sides with Flagg in defeating their plans.