The story of Mexican American miners -- "los mineros" -- whose pitched labor battles, beginning with the first strike in 1903, shaped the course of Arizona history. It was only in 1946 that the two-tier wage system for whites and Mexicans was abolished. The film recounts the rise and fall of three small towns -- Superior, Clifton-Morenci and Sonora -- where the mining of copper ore dominated the lives of all the inhabitants.