Rod Cameron is Captain Webb Calhoun, leader of a band of misfit soldiers assigned to enforce a treaty with the Sioux indians. Cameron and his gang must ensure that the settlers in the area obey the treaty and leave the land, but the matter is complicated by the discovery of gold in the area. Complicating things further, Calhoun gets a new commanding officer, Lieutenant Colonel Unger (Forrest Tucker), who has absolutely no respect for him and dresses Cameron down every chance he gets. Soon things get worse when the two begin to butt heads over sultry saloon girl Lia Wilson (Adrian Booth), and the situation with the Sioux totally breaks down.

As Herbert J. Yates of Republic Pictures was losing his stable of cowboy stars to television and other studios, he started doing serious westerns such as this one. Oh! Susanna - the song is heard over the title credits and not again - is a good cavalry western that borrows a great deal from the John Ford classic Fort Apache. They even use the same song about 40 miles a day on beans and hay. And John Ford regular Jack Pennick, an old real-life horse cavalryman, was technical adviser. Director Joseph Kane cut his teeth on campy Gene Autry and Roy Rogers features, and was now branching into more serious work. Like Fort Apache, the conflict is between two officers - new commander Lieutenant Colonel Forrest Tucker and Rod Cameron the captain who was in charge of the fort before. Tucker rose through the ranks the hard way, and he truly hates West Point types like Cameron. Especially those like Cameron who take their orders seriously about keeping settlers out of the Sioux's sacred Black Hills territory. Cameron and Tucker are also rivals for Lorna Gray who works in Jim Davis's saloon and Davis has an interest in her as well. Tucker has no compunction about pulling rank.Chill Wills plays the sergeant assigned to Cameron's platoon who narrates at the beginning and the end and it is his eyes through which the film is seen. This is one of Chill Wills's best screen roles.