In the summer of 1879, young Ben Drake travels to the town of Mason in New Mexico. The 18-year-old aims to find out the truth about his father's death at the hands of a lynch-mob, but soon the events which led to his father's death cast his own life into hazard. Drake finds himself drawn into the Mason County War, in which a band of young men challenge the iron rule of businessman Angus McBride who seems to have the authorities at his beck and call. The confrontation culminates in the youngsters fighting against a troop of US Cavalry, in what will come to be called the Battle of Grover's Mill.