Chapter I - A friend in need
In Waterdeep, a gold coin is called a dragon. And when you heard about an open hunt for half a million of them, you knew what your next destination was.
You heard the full story of the treasure hunt from Peter Theodonos, a travelling scholar you had the luck of meeting one night on the road. You let him into your camp and granted him protection and in turn he told you the story of Waterdeep's biggest treasure vault:
Before he was ousted from his position as the Open Lord of Waterdeep, Dagult Neverember embezzled half a million dragons and hid them in a secret vault. Built long ago by dwarves, the vault is warded against all forms of magical detection and intrusion. Its current protector is an adult gold dragon named Aurinax. As another security precaution, he arranged for all knowledge of the vault's location and defences to be magically erased from his mind and the minds of his subordinates. The wizard who performed the procedure trapped this knowledge within an artefact called the Stone of Golorr. One way or another, the wizard disappeared shortly thereafter and Dagult hid the stone in the Palace of Waterdeep. Dagult was off rebuilding the city of Neverwinter when the other Lords of Waterdeep voted him out of office. He immediately made plans to retrieve the Stone of Golorr and smuggle his cache of dragons out of Waterdeep. His spies plucked the stone from the palace but were killed while trying to leave the city. The stone was stolen and passed from one hand to another like a common jewel until it wound up in the clutches of Xanathar, a paranoid, megalomaniacal crime lord. And from here on, every trace of the Stone is lost.
Peter left your camp the next morning, while you debated weather or not you should go join the hunt. You did not debate for long.
Waterdeep is a huge city on the coast, one that would take days to fully see and decades to learn all of its secrets. Thankfully, you only need the one. You stride straight toward the Yawning Portal, a well know inn and a hub for adventurers in the centre of the city. A great place to start your investigation or overhear any whispers.
You find The Yawning Portal in the Castle Ward of Waterdeep. The place is a stone building with a slate roof and several chimneys. Most of the ground floor is taken up by the tavern's common room, which contains a 40-foot-diameter open well (actually the outer shell of a sunken stone tower) that descends 140 feet to the first level of Undermountain, the sprawling dungeon under Waterdeep. A rope-and-pulley mechanism is used to lower adventurers into the well and hoist them out. Not that you want to go dungeon crawling right now.
There, sitting at a table with a drink (or without one) you have the time to reflect on why are you here. What made you want to join the hunt for the embezzled dragons?