"There are a lot of shipwrecks around these islands. He wanted us to find a ring, a necklace, a music box and a key. He promised to reward us in ways we can't imagine so I accepted it."
Were you able to continue with this mission? I played it a long time ago and at the beginning it was quite a challenge the little space they give you until you upgrade the ship parts xD I also made the mistake of going out at night so you can imagine that I didn't do well trying to avoid the rocks that appeared in front of me and the sea creatures.
I did find one of the items, a big key. But I am not actively looking for them. I wanted to do some upgrades first. The limited space is quite a challenge for me too. You catch a few fish and you have to come back to sell them. xD