The players were sent to Thunderspire Mountain to deliver a package to Gendar Malyn, a drow merchant. Beneath the mountain is a ruined minotaur city. Before they reached the city, they found a halfling being held captive by hobgoblins. They rescued him and he explained his name was Rendil Halfmoon, and the hobgoblins were part of a group of slavers called the Bloodreavers. Rendil led them to the Seven-Pillared Hall, a outpost in the city. The hall is a large underground area, filled with traders. It is administrated by the Mages of Saruun, who make money by taxing the valuable surface-to-Underdark trade. After delivering the package to Gendar, they set off to find and shut down the goblin slaver operation.