On the Texas frontier in the 1840s, a red-haired child whose family has been massacred is captured by a Comanche war party led by a great warrior named Buffalo Caller. The boy is rescued by Mike Shannon, a Mexican War veteran riding with a "ranging company" of Texans dedicated to protecting settlers against Indian raids, and is adopted by the Shannon family. In 1861 his adoptive father is bushwhacked and murdered and the boy—now known as Rusty Shannon—follows Mike's footsteps, riding to Fort Belknap to join the Rangers. Texas is now in the throes of secession and Union sympathizers are treated as traitors. One such "traitor" is Lon Monahan, whose family befriends Rusty. Lon Monahan's particular enemy is Colonel Caleb Dawkins, a former army officer and Confederate zealot determined to conscript the Monahan boys and drive Lon and all Unionists out of Texas. When the youngest Monahan attempts to escape Texas and wait out the war, Dawkins's thugs hang him and his father. Rusty Shannon carries heavy burdens. Both of his families are dead; he is haunted by Mike Shannon's murder, thinks he knows the culprit and intends to kill the man; his new-found friends have been lynched; and his duties as a Ranger conflict with his sense of justice. And he is fated to meet again the Comanche warrior whose band killed his family and took him captive over two decades ago: Buffalo Caller.