A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.
Five men are herding fifteen horses down the road. They won't be very talkative, but are willing to sell a horse, or more horses if the heroes are interested. These men are horse thieves. They are already sought by regional militiamen. Anyone with a stolen horse (all are marked) may get into trouble. If found guilty, horse thieves face prison or even a hanging execution. Similar thefts have happened only a month before, and a reward is offered.