Sea Devil Note and Key

A heavy, brass key with an inscription down the stem in ancient giant, paired with a map and a note.
The note reads, "We've found the right lot number - hire some fool to bid on it for us, and bring the map and key back. Once we have the other key from the site on the islands, we'll be able to get into the facility, and the treasures of Keht Pradahk will be ours. All the glory and wealth that the Kapaerian Sea outpost deserves will finally arrive. Oh, and get rid of whoever buys the key for us, we don't want this traced back"
The map shows a few small islands marked with the symbol of a key, with a dotted line leading north into a mountainous region, marked with two keys