In the summer of 1862, two great armies met outside of Richmond in a series of battles that would determine the course of the Civil War. The Union had time, men and materiel on its side, while the Confederates had mobility, esprit de corps and aggressive leadership. Untried General Robert E. Lee was tasked with driving the Yankees from their almost impregnable positions to save Richmond and end the war. Lee planned to isolate part of the Union Army, crush it, and then destroy the only supply base the remaining Federals had. To do so, he had to move thousands of troops hundreds of miles, bringing multiple forces together with intricate timing, all without the Yankees or their spies finding out. The largest and most important of these battles occurred at Gaines' Mill.