Its a quest called "lost lewts". You have to find the quest in the Road Ends, its in a side cave to the left of the map before you fight that one Admiral or w/e he was. You run down a path into a shack in this cave. There is a red treasure chest in the shack, and when it opens up, only a recorder looking device is there, its actually the machine that starts the quest. You have to have a Lancer vehicle, and it acts as a sonar, showing when your near a buried treasure.