In 1890 Wyoming, James Averill is the Sherriff of Johnson County, which is largely inhabited by foreign immigrants. The wealthy cattle owners view the immigrant farmers as a nuisance and hindrance to them enlarging their own land. The cattlemen's association, the Wyoming Stock Growers Association, effectively declares war on the immigrant farmers and gets the state government's blessing. They assemble an army of guns-for-hire and, backed by the U.S. Cavalry, set out to rid the state of the immigrants. James Averill's heart is with the immigrants, but he doesn't think they have a chance of winning the inevitable war.