Cowboys Luke Stuart and Tom Schurtz meet in the infamous Dodge City at the end of their trail drives in 1877. Together, they ride back to Texas, where Luke and his wife, Elizabeth, divulge a secret plan to Tom. The Stuarts and Tom subsequently form a partnership and venture out into the distant frontier to establish a ranch in the canyons region of the Llano Estacado, only recently (and not completely) vacated by the Comanche. They seek a place of mystery, Canyon Escondido, which may not exist. They have learned of the canyon from neighbors, whose sources are family lore and the legends of their peoples, Apache and Mexican. In hope, the pioneers, including the Stuart children and Andy Grady, drive their herd across the rolling plains, through notorious frontier settlements and the wanton buffalo slaughter. Their determination will be tested by the challenges meted out along the path they have chosen, not least so when they finally face the success or failure of their quest and what must then follow.