It's 1861 and the Civil War is about to break out - making life in the US Army tense and divided. Lt. Jed Sayre (Audie Murphy) is trying to hold his outfit at Fort Union together while tempers flare, but the situation gets worse when they get a new southern sympathizer CO in the form of Captain Lee Whitlock (Robert Sterling), who has brought along his lovely but spoiled (and racist) sister Marcy (Joan Evans). Captain Whitlock sets out to whip the camp into shape, but there's trouble afoot with the Navajos on their reservation. Sayre has spent time building a good relationship with the Indian Chief Menguito (Dennis Weaver), but Captain Whitlock has secret designs to ensure a confrontation so the fort will be weakened when war breaks out, allowing the Confederate Army to easily capture it. Fellow Confederate sympathizer General Ray Collins is also in on the plan, making Audie's attempts to set things right almost impossible.

It is claimed that this is the only western in movie history in which the Native Americans occupy a fort and are held under siege, surrounded by the US Cavalry. Column South has many interesting quirks, including the ever-looming subtext of the upcoming Civil War and its effects on the attitudes and functionality of the US Army. The film is directed by Frederick de Cordova and written by William Sackheim. It stars Audie Murphy, Joan Evans, Robert Sterling, Dennis Weaver and Ray Collins. Music is scored by Joseph Gershenson and photography by Charles P. Boyle. Film buffs will enjoy seeing many familiar faces in the cast (Bob Steele, Greg Palmer, Russell Johnson, Dennis Weaver and Ray Collins.)