Word had come into General Robert E. Lee's headquarters that the Union trenches were empty. His suspicion that they were retreating was correct, and he quickly devised a plan of pursuit. The three divisions north of the Chickahominy River, commanded by Generals Longstreet, A.P. Hill and Jackson (who now commanded D.H. Hill's men as well), were ordered to cross, but only Jackson was given a key role to play. Longstreet and A.P. Hill were too far away to be of any use, though they were also crossed.…