During Act 2 in the Docks at night you will be able to enter the Disused Passage. There inside a sack you will find an item called "Waxler's Hat". Loot the item and a new quest will appear in your journal.
Head to The Hanged Man at night and hand over the hat to its owner for a reward.
- 750 XP
- The quest may not mark the tavern as the final place to go to complete the quest. (pcxbox360ps31.03)