Lel, Fargrim, and Fist travel through the seven-pillared hall and to the market at Horned Hold.
Fargrim heads out from Castle Artegia on a joyful walk when he discovers a Yuan-Ti temple, he enters it and discovers one of the Warforged from Akkadia being attacked by the serpant cultists inside. Both of them are saved by Lel who jumps into the temple, they activate a trap and barely flee from the temple with their lives.
Finally deciding to investigate the rumors that there are more Elder Eye Stones beneath Thunderspire Mountain, the party sets off near the Western Kingdoms and journeys under the mountain. Shortly after going underground they discover a labyrinth of tunnels and come upon a large hall with seven pillars that appears to have once been a bustling market and living area, but is now abandoned. There they discover an old Duergar trading outpost that was trashed, but found hints of recent use as a place for storing gems and metal items, as well as rooms filled with writing in Deep Speech on the walls. Several frequently used roads lead through the hall, most notably of dwarven carts from north to south.
Following the tracks south, the party comes to a large undeground chasm with a strangely constructed stone city spanning both sides of the chasm, with three bridges connecting across it. The party enters Horned Hold through the Duergar entrance, offering them some cooked Spider Bits once they pass through. Across the chasm from the Duergar fortress they discover a bustling market place inside of Horned Hold run by minotaurs and overseen by a head minotaur with a racism problem, named Asteron.
Asteron immediately notices the usefulness of Lel as he is not a Duergar but speaks Deep Speech, and offers them a place to stay in the Hold in return for help with finding out if the Duergar are in fact attacking caravans within the Labyrinth.