Card shark Jeannie Lowry (aka "Texas Lightning") hires Magnum as her bodyguard at a high-stakes poker game aboard a luxurious yacht. But Magnum soon learns that the poker game is just a facade and Jeannie is hiding something about her true intentions. Magnum and Jeannie are forced to make a hasty escape from the yacht and become stranded on a deserted island, and are presumed dead.