Confederate general Joseph O. Shelby and his legendary Iron Brigade refused to acknowledge the end of the Civil War. Instead, they fought their way to Mexico in search of a place where they could continue to defy the U.S. government. These veteran Missouri cavalrymen clawed their way for fifteen hundred miles, fighting Juaristas, Indians, desperados, and disgruntled gringos. They disbanded only after they had offered their services to Emperor Maximilian and were turned down.

Shelby's adjutant, journalist John N. Edwards, first published his story of the exploits of this superb mounted brigade and its quixotic final march in 1872. Conger Beasley provides a lively introduction that includes the first biographical sketch of the author. The 1969 movie The Undefeated starring John Wayne and Rock Hudson was based upon Shelby's expedition.