Young engineer Francesco Ferraro (Enzo Bottesini) is sent to Smeraldo Island in the Seychelles to oversee the tests necessary to dig a silver mine. But Francesco must also find out what happened to his predecessor, vanished without trace. The island seems to be an Eden on Earth, and the native girls freely explore the joys of sex, but there is something in the dark working against Francesco, and a mysterious accident disables his delicate equipment.