Ah, the brew! Thank you. You have done well. I hope the journey didn't cause you too much trouble. Now, I suppose you'll be wanting information regarding that chest? Very well.
A few years back another came in search of such a chest. A strange man who seemed dead set on finding it at all costs. He went only by the alias, "The Innkeeper." At the time the cursed chest was in our possession and he offered us a substantial amount of gold in exchange for the item. Seeing as we didn't have the knowledge to open it, it seemed rather useless to keep it so we gave it to him in exchange for the gold.
I imagine this "Innkeeper" would still have such an item. Speak to him, and good luck on our journey.
Then the player just need to go to an Inn and talk to the Innkeeper about the cursed chest and start the fourth and final quest, The Lost Jewel.