Veteran marshal James Flagg (Robert Mitchum) and his long-time nemesis, gunslinger Big John McKay (George Kennedy), team up to prevent a train robbery in this comic Western. Flagg's been forced to retire by an arrogant mayor, and young hotshot outlaw Waco (David Carradine) has put McKay out to pasture. With the clueless town politicians refusing to heed their warnings about the pending crime, the unlikely duo takes matters into their own hands.