You are now in Baron town, here is the item checklist:

• 2000 gil
• Zeus's Wrath
• 1000 gil

Here is things you have to do:

1. Talk to Yang at 2F in the INN, but you have to snap him out in a battle then he'll rejoin your party.
2. Use Baron key to unlock weapon store for treasures. When you are, don't forget to talk to Jammingway the rabbit.
3. Go to #3 and enter Ancient Waterway.