It is said by the village gray beards Of Breen, that the band of human exiles who founded their prosperous farming settelment almost a century ago,had to fight a long,savage struggle with the original inhabitants of the fertile valley;monstrous trolls that saw the new arrivals as meals, rather than as potential neighbours.After 5 long years, the humans with their superior steel weapons, drove the troll tribe into the bleak highlands and hills sourounding the valley.But as time passed, the old tale begun to become legend, rather than history and is regarded by most, as a mere story used by parents to frighten disobediant children.And yet the village leaders have always forbidden their people from wandering the hills....
After the PCs defeat (or force the rapid retreat of) a villanous necromancer/demon summoner, they discover a book. This book outlines how to summon a demon whose power increases according to the size of the summoning circle used to summon it. And after the PCs examine a map of the country, they find that the layout of the cities and roads match up with the required summoning circle. In fact, the final road that would complete the circle is currently in construction.
With anyone who can find out about the circle and the ritual to summon the demon able to somehow make the final road/line, and destruction of the cities and roads currently in existence out of the question (unless this is an evil campaign- that removes the moral quandary), how are the PCs going to solve this problem?