Dr. Claudia Harding is a scientist at the Maritime Institute in Hamburg and, after years of research, has found the site of a sunken ship containing a precious emerald. She travels to Grenada and meets the charismatic skipper Richard "Rick" Bertold. Although he has a doctorate, he now prefers to live as an adventurer and treasure hunter. Together with the crew of the salvage ship, they set off in search of the ship. But Claudia soon realizes that there is a traitor on board.