Johnny, Jill and Luke, invited by Uncle Martin, go for vacation on a tropical little island: a very Paradise of the Nature, where sun, sea and fun becomes the three guys' world. But the greatest attraction of Dive Island in the underwater world, where a wonderful coral reef is home of fishes of thousands shapes, colors and sizes. The three guys will learn to dive thanks to Antonio, the diving instructor of the Island, starting from base courses, up to become expert divers. The marine biologist Lucia will often ask for their support in the task of sea-life care and protection. The photo-reporter Mark will teach them the underwater photography art, supporting them with equipment and advices But a hidden truth will emerge from the abyss of the sea and, thanks to Uncle Martin's lore, it will make our young protagonists more and more involved: was really Dive Island a pirates' cove in the past? … and maybe the galleon of the dread "Red Beard the One-Eyed" sank in the waters nearby…!?!