We can never know what frantic thoughts raced through George Armstrong Custer’s mind in the last hour of his life. But surely, as ever-growing numbers of angry, well-armed Plains Indians closed in on his 210 troopers of the 7th Cavalry, he must have realized that he had fatally misjudged the size of the hostile force now surrounding him. His plan to subdue a large Indian village had completely broken down. He had been warned repeatedly by his scouts that his target, an Indian encampment on Montana’s Little Bighorn River, was far larger than he had imagined. Now, on this very...