A band of adventurers led by the human Tiriande found themselves trapped in a seemingly endless dungeon after disappearing on a quest. Unable to find a way home, they formed alliances with a clan of orcs and a tribe of merfolk, founding an outpost that would, over the next few decades, grow into a village known then as Sar-Vistu - Netherese for Basecamp.
The death of their wife causes Tiriande to become obsessed with finding a way back to the Material Plane, and they disappear on an expedition to find one.