Here, a band of adventurers from Icewind Dale found Jarlaxle, and they exchanged information. He informed the party that the people captured from their village might be used as fodder in a war between drow houses, in which they would be sent forth to activate the protective glyphs.
On the advice of Rizzen Do'Urden, the companions returned to Gollvelius' Tavern to speak again with Jarlaxle. He made a promise to supply them with the House Do'Urden insignia, in exchange for a golden necklace, found in the Mantle caverns. Jarlaxle didn't fully commit to his promise, but instead revealed to the party that a drow patrol of young nobles carried the insignia in another set of caverns nearby.