One year after the end of the Civil War, three southerners are heading northwest on the Bozeman Trail to the gold mining camp at Virginia City. When they find the army has closed the trail because the Sioux are on the warpath, they accept work at Fort Phil Kearny. After an Indian ambush, the men flee the fort, together with a man called Slade. But when Slade is revealed as a hired gun and murderer, the southerners are drawn into the hunt to apprehend him to clear their names.