A semi-abandoned fortress stands guard between two rivers, making a spirited attempt at checking the enemy advance. Your foes have constructed towers on the opposing hilltops, countering your move.
Build your forces, aid your allies, and use the fortress to your advantage. There are a host of hills and valleys to hide, plan, and slowly wear down your foes.
Note: A siege tower will help you gain the towers and walls of the fortress. I chose the upper left keep and had my two allies directly below and directly opposite mine. Most AI's work well on this map.