You come across a bandit fortress, with walls, a small keep, and a few other buildings. It turns out they’ve recently attacked a traveling caravan, stolen the supplies, and taken prisoners! By laying siege to the camp you can take out the bandits (which could slow down the rate of bandit raids on your town), which would grant you the supplies they stole and the prisoners as new citizens, or you can work with the bandits, help them take caravans in return for some of the profit, but other settlements around you would become annoyed and possibly declare war.