With the civil war over, the president assassinated, and the South in reconstruction, Tyrell Thompsett knew the country would be crying for beef. His long-held dream was to have his own ranch and to follow in the footsteps of his father that started the first ranch in the Medicine Bow range of Wyoming territory. Now, with his new wife, a member of the Pueblo Indians of New Mexico, and his friend, Grey Wolf and his wife of the Mouache Ute, he set out to make that dream a reality. But it seemed like the forces of nature had conspired together against them, and to add in the Weeminuche Ute, Jicarilla Apache, and some renegade Comanche, the obstacles before them seemed insurmountable.

But after locating the ranch on the upper reaches of the Rio Grande in the San Juan mountains, the real challenges had to be faced. With a herd waiting in New Mexico territory, they set out to bring the herd back to Colorado territory. But, when a newly formed band of outlaw Confederate rebels, traders known as Comancheros, and renegade Comanche from the bands of the Ditsahkanah and Penateka Comanche, the name Comanchero referred to a heartless and merciless band of murderers and thieves.

And it was to be a battle between the vaqueros and cowboys against the Comancheros that would leave a trail of blood and bodies and determine the fate of the Rio Grande ranch and the future of Tyrell Thompsett in the San Juan mountains.