December 1777. It is 18 months after the signing of the Declaration of Independence, and some 12,000 members of America's beleaguered Continental Army stagger into a small Pennsylvania encampment 23 miles northwest of British-occupied Philadelphia. The starving and half-naked force is reeling from a string of demoralizing defeats at the hands of King George III's army, and are barely equipped to survive the coming winter. Their commander in chief,...