Secrets of the Underdark

Easter leads the party toward the old miners' quarters where he remembers the gold vein. They find instead a chamber dug far beyond his memory, with a live campfire and a stone altar of Laduguer bearing a glowing green gem. Four invisible duergar guard it. La Maestra bluffs them with a claimed vision from their god, then pries the gem free anyway. The altar chamber collapses, and Aelion is saved only by a healing potion Easter had hidden in his sock.

During the rest that follows, Aelion attunes to his maul and it reveals itself as a Holy Avenger. Behind the shattered statue is a one-way mirror portal, and beyond it a ruined wizard's chamber, a warded chest, and drow-held caves. There is no way back.