This Island Isn't Big Enough

When Rick's boat returns from a cruise deserted, Magnum searches for the answers to what has happened to his friend and the passengers on-board, who are all presumed dead. His hunt is somewhat hampered by the separate investigation of a law officer who models himself on John Wayne, but as they both try to get to the bottom of the strange disappearance of the boat's passengers, they stumble upon a plot involving mobsters and two million dollars in counterfeit money...