This pilot launches the saga of the Cannon family as they fight to establish a ranch in the Arizona territory of the 1870s. Marauding Apaches led by Cochise are on the warpath. The Army orders the Cannon family to move on, but Big John Cannon won't budge. While his brother Buck rides off to recruit gun-carrying cowhands, Big John learns of another enemy: a Mexican land baron claims the Cannon property, and dispatches his men to seize the cattle.