The Hollow Earth
Xiff's House (map)
Xiff’s house, once presumed to be a getaway for Ezren’s father, was located at the top of a hill in Freehold, a town southeast of Arroes. It was the spawn point of shadow creatures from another dimension that preyed on the townsfolk after Xiff tried to help them deal with their kobold problem.
Oh yeah, and there were LASERS the players got to bounce around the dungeon!