An Important Invitation

 is the first quest in the Undermountain Campaign in which an invitation behind Sargeant Knox takes you to meet with Lord Neverember in Moonstone Mask.

Steps

 * Embark on Neverember's Quest
 * Meet with Neverember
 * Meet with Lord Neverember    
 * Talk to Jarlaxle at the Bar Downstairs
 * Enter Undermountain
 * Talk to Jarlaxle
 * Take the Longboat to Shore
 * Clear a Path to the Encampment    
 * Enter the Beach Encampment
 * Talk to the Adventure Party Leader
 * Talk to the Adventurers
 * Enter the Portal
 * Enter the Dungeon
 * Explore Deeper
 * Follow the Tunnel
 * Climb to Safety
 * Talk to the Bartender