If you choose to accept Gatewarden's offer, you will be taken to the Storage Cellars and meet up with Obe. Note: This isn't "really" a quest (or subquest or side quest), as it doesn't show up in your Journal, as all good quests do. It is initiated via dialog, like a quest, but lacks clearly defined goals and tangible rewards. Here you will be given temporary control over 5 companions, giving you a full party of 6 to lead. After a 10 turns he will teleport you back out without asking. Obe's excuse is that his illusions begin to get real if he's been conjuring for too long without a break.