The year is 1916. The enemy, Pancho Villa, is elusive. The terrain is unforgiving, the intense heat and dust both relentless and overpowering. Through the mountains and across the long dry stretches of Mexico, Napoleon Childs, an aging cavalryman, leads an expedition of inexperienced horse soldiers on seemingly fruitless searches. Napoleon has weathered the storms of battle with a toughness that has become like a second skin, with the Rattler, a horse who's as flinty and seasoned as he. But this time, Napoleon can't control one of his young soldiers who has a penchant for reckless, dramatic actions--and who singlehandedly, in his desire to prove himself, makes a move that is the beginning of the end. Before long, Napoleon's patrol is at the mercy of an enemy who is intent not only on killing Napoleon's men but on something much bigger: avenging a brutal act.