Found (#2 Flamestone Trilogy‪)‬

Still reeling from the revelation that her present family is involved in the Flamestone Society, Elaine has made it to a rugged settlement called Wompitt, a town made up of escapees from the Dweller mines. That's good, because she's going to need all the help she can get to rescue her friends from the mines and stop the evil Society from selling any more souls to the depths.

Or is it? It seems the people of Wompitt have one thing on their mind: survival, and nothing else. Worse, the leader of Wompitt thinks she might have connections to the Society, and there's only one punishment for that—death. And it gets even worse than that. Someone inside the walls really is working against them all, and Elaine's the top suspect. Can she survive long enough to mount a rescue mission for her friends?