The king forsees a large-scale war in the future, but he lacks the materials needed to fight such a battle. Being caught up in a conflict with the Snake, he also lacks the time to acquire the needed materials. Hence, he has called upon your services to get the needed goods.
Your fortress is set against a beautiful mountain landscape, with a river running directly through your city and stone bridges to get your people from area to area. These bridges hold a significant value, as they are the only way to access half of your city. Wood is plentiful, but the other materials you may have to scramble to get ahold of in time. The market trader refuses to buy raw materials in this area, but you can get processed goods easily.
Don't expect the Wolf to just sit back and let this happen. As soon as he gets word of what is going on, he is sure to send a large invasion force. While defense is a very important part of this campaign, don't let it get too important or you will not be able to acquire the needed goods. Don't count random events out of the picture, either. Remember, this is a normal fortress, not a Utopia. Not everything works perfectly.