Mace Brown wasn't his real name. He used to be one of the deadliest gunfighters in the Southwest, but eventually he grew tired of the "kill or be killed" lifestyle, rode off into the desert—and simply disappeared. When Boston archeologist Dr. Jemima Carstairs arrives in Oneida, Texas to survey and study ancient Indian ruins in the Palo Duro Canyon, Mace reluctantly agrees to lead the expedition. Unaware that a gang of outlaws is dogging their heels, and a Comanche war chief and his band of renegades are also roaming the plains south of Oneida, Mace and his crew set off with the archeologists into Palo Duro country. Their scholarly quest for Native American artifacts will quickly become a struggle for survival.