Will Kane, the sheriff of a small town in New Mexico, learns a notorious outlaw he put in jail has been freed, and will be arriving on the noon train. Knowing the outlaw and his gang are coming to kill him, Kane is determined to stand his ground, so he attempts to gather a posse from among the local townspeople.
Wealthy rancher Bick Benedict and dirt-poor cowboy Jett Rink both woo Leslie Lynnton, a beautiful young woman from Maryland who is new to Texas. She marries Benedict, but she is shocked by the racial bigotry of the White Texans against the local people of Mexican descent. Rink discovers oil on a small plot of land, and while he uses his vast, new wealth to buy all the land surrounding the Benedict ranch, the Benedict's disagreement over prejudice fuels conflict that runs across generations.
Schoolteacher Bertram Cates is arrested for teaching his students Darwin's theory of evolution. The case receives national attention and one of the newspaper reporters, E.K. Hornbeck, arranges to bring in renowned defense attorney and atheist Henry Drummond to defend Cates. The prosecutor, Matthew Brady is a former presidential candidate, famous evangelist, and old adversary of Drummond.
