Falcon MacCallister never thought he'd wear army brass. But Colorado is about to join the Union—and the would-be state has just made him Lt. Colonel in its Home Guard. Then, before his military career can take off, Falcon loses one of his men and two deadly new Gatling guns to a murderous ambush. Falcon is going to get those Gatling guns back—before they kill the wrong people.

Tracing the missing guns to Eastern Montana, Falcon teams up with a scout named Isaiah Dorman. Falcon and Dorman are spearheading a battle against the Sioux—in the shadow of the disastrous Little Big Horn slaughter. For the two men, survival along the Little Bighorn is going to mean breaking rules, standing strong, standing together—and holding off a deadly onslaught with only a few guns against many…