What do Jack and Harry see when they look though the gap after a unnatural North wind begins to blow and what do they do?

Jack and Harry nose into the Gap, and see a huge rider leading the army on a white horse, with a banner carrier to his right. As arrows begin to fly from the filanon, Harry and her army storms through the gap to meet the Northerners, and they successfully drive the Northerners back, for a time.