Border River stars Joel McCrea as idealistic Confederate major Clete Mattson and Yvonne DeCarlo as saloon owner Carmelita Carlas. With the South facing defeat, Mattson desperately tries to save his army by stealing $2,000,000 in Union gold. He then heads to a raucous border town on the Rio Grande, hoping to make a munitions deal with Mexican general Calleja (Pedro Armendariz). But first, Mattson must contend with Calleja's double-crossing German military advisor Baron Von Holden (Ivan Triesault), not to mention Calleja's tempestuous sweetheart Carmelita, who is likewise not to be trusted. Alfonso Bedoya engagingly goes through one of his "We don't got to show you any stinkin' badges" characterizations as Calleja's aide-de-camp.
by Hal Erickson synopsis