Their journey takes them into the heart of the dangerous Llano Estacado region known as the Comancheria. The area is ruthlessly defended by a band of Quahadi Comanche and their stoic leader, Lonely Horse. The Troop encounters a large group of Comanches and the gun-running Comancheros at Mushaway Mountain, close to Gail, Texas. A quick battle ensues that leaves eight men dead.

Post Cavalry life finds Tree Smith and Cedar Jones as cowhand and cook on the large Rolling J cattle ranch in South Texas bordering the Rio Grande River. The ranch employs two Vaqueros from the village of Montenegro in Mexico, just across the river, whom Tree befriends.

The quiet life on the Rolling J ranch is brought to an abrupt halt when a local sheriff warns that a band led by the cold-blooded, sadistic killer known as Gato Montes has been preying on the ranches along the Rio Grande. After the sheriff is nearly killed by these men, Tree is tasked with tracking them down, only this time, he is traveling alone and the dangers are greatly multiplied. His epic journey takes him back into the Llano Estacado where he is captured by Lonely Horse and taken to Mushaway Mountain where the Comanche carry out their own form of frontier justice.

Tree's return journey puts him on the same path as Marco, a Mexican goat herder, who rides with him to the Mexican Village of Montenegro, where Tree meets Julia, who changes his life forever after he becomes involved in and bears witness to the wonderful celebration of Dia de los Muertos.