Coming along as uncle Quentin's firm is contracted for a development project by tycoon Haynes on a tropical (fictitious SE Asian) island , Julian, Dick and Timmy are eager to turn their beach holiday into an adventure. Accidentally diving up a brass locket, a clue, they dream of discovering a pirate treasure, buried in the jungle. It's mentioned in legend, known to fresh local girl 'Joe', who eagerly tags along, hoping to earn enough to redeem her broke village facing expropriation. But the western couple who run the tourist beach bar get wind of the project and are determined to steal the treasure. Julian soldiered on bitten by an insect, but the poison makes him collapse, in urgent need of rare antidote only growing on the mountain top. It's a dangerous there, to the treasure and back to the resort, where more nasty surprises await.
—KGF Vissers