The Underground (snippet)(full version to be on ao3 soon)

4 people from a seemingly normal town are selected to solves a great mystery, a underground city has been unexplored since it was first found centurys ago, but ones who have tried to explore it before , never returned, the 4 selected ask 5 others to join them in the journey and are determined to succeed in finding out what the hell is up with this abandoned city . while they are trying to do this a murder happens to one of their dearest friends , which ties to the mystery as well. the person they think is trying to help them is really the one who is causing this distress.