Empire of the Summer Moon spans two astonishing stories. The first traces the rise and fall of the Comanches, the most powerful Indian tribe in American history. The second is the epic saga of the pioneer woman Cynthia Ann Parker and her mixed-blood son Quanah, who became the last and greatest chief of the Comanches.

Although readers may be more familiar with the tribal names Apache and Sioux, it was in fact the legendary fighting ability of the Comanches that determined just how and when the American West opened up. Comanche boys became adept bareback riders by age six; full Comanche braves were considered the best horsemen who ever rode. They were so masterful at war and so skilful with their arrows and lances that they stopped the northern drive of colonial Spain from Mexico and halted the French expansion westward from Louisiana. White settlers arriving in Texas from the eastern United States were surprised to find the frontier being rolled backward by Comanches incensed by the invasion of their tribal lands.