U. S. Marshal Lance Kincaid accepted an assignment from the governor of the New Mexico Territory to act as an undercover agent. His mission was to investigate the violence and crime in the Silver City area, identify the people responsible for such activities and bring them to justice.. Lance began to suspect the violence in the area not only involved the Apaches, but also city ruffians, the Indian agent, the territory politicians and perhaps the military. The gunslinger, John Kinney, was determined to have Lance killed.