Nathaniel Philbrick turns to the tragic relationship between George Washington and Benedict Arnold. In September 1776, the vulnerable Continental army under an unsure George Washington evacuated New York after a devastating defeat by the British army. Three weeks later, one of his favorite generals, Benedict Arnold, miraculously succeeded in postponing the British naval advance down Lake Champlain that might have lost the war. As this book ends, four years later Washington has vanquished his demons, and Arnold has fled to the enemy. America was forced at last to realize that the real threat to its liberties might not come from without but from within.