In September 1862, Robert E. Lee led the Army of Northern Virginia north of the Potomac River for the time as part of his Northern invasion, seeking a quick end to the war. Lee divided his army in three, sending General James Longstreet north to Hagerstown and Stonewall Jackson south to Harper's Ferry. It was at three mountain passes, referred to as South Mountain, that Lee's army met the Federal forces commanded by General George B. McClellan on September 14. In a fierce day-long battle spread out across miles of rugged, mountainous terrain, McClellan defeated Lee but the Confederates did tie up the Federals long enough to allow Jackson's conquest of Harper's Ferry. Join historian John Hoptak as he narrates the critical Battle of South Mountain, long overshadowed by the Battle of Antietam.