Between Two Worlds
The Bandits of Kvatch
The isolated village of Kvatch, known for their rich metal mines, has always had problems with bandits, so they saved as much as they could and hired a group of mercenaries to deal with the bandits. Upon saving up enough money they reached out to a powerful group of adventurers, the Dragon Knights of Samtara. They knights came in and defeated the bandits easily enough but after collecting the debt they left a small group of them in the bandit's camp who now collects a protection fee from the village. The dragon knights claim this is a group of renegades and have no ability to stop them. The villagers are now skittish and are hesitant to trust strangers; they don't reach out to the players, the players will have to collect details themselves in order to find out about this. If the players ever question the villagers about this and suggest that they could deal with them, the villagers will just act terrified and demand that the players leave this alone, that outsiders have done enough damage and they would only make things worse.
The mercs are set up about 1 hour out of town; they can convince the townsfolk to tell them, or find them via tracking or magic. The dragon knights live in a set of tents and shabby hunts the bandits used. There are 7 mercs as shown on the map below:
Once the players have beat the bandits, if they explore further they may discover a large dark cave sealed off with a portcullis. Any attempt to get past it or see what's in it infuriates the resident, an ancient white dragon. (CR20) who knocks down the portcullis and attacks the party. If the party defeats the mercs but don't find the dragon, after they arrive back in town and announce defeating the mercs there is rejoicing. Meanwhile the dragon breaks free of it's cave and flies to the town to attack it. (Maybe preface it by having the village elder cry out something like, "I can't believe you defeated those mercs and their dragon!")
Differences in the World
The dragon is White.
The dragon is Black.
The players are rewarded with ice cream and lollipops.
Impact on the World
The players gain a little reknown and are known for killing dragons.