Adventure series in exotic locations. This adventure is set in the exotic Island of Hawaii and involves the search for a missing sloop and the whereabouts of a valuable mine. Biff Brewster, his father and friends become entangled with ruthless criminals who are also intending to find the sunken boat and discover the map and the mine. They have kidnapped the elderly scientist who holds the key to the discovery. An exciting adventure with lots of action on land and sea.- Summary by Peter Thomlinson