What a surprise twelve-year old Emma Mae and her ten-year old brother Edward find when they stop at the very deep and dangerous Blue Pool near their home in rural West Kentucky in 1914. They encounter a beautiful rainbow-colored fish that floats in the air and talks! But what is even more surprising is the way in which that fish will later transport them and their younger brother William through underwater passages all the way to the ocean and up the coastline to the beautiful Campobello Island where there is a family in great need. How can they identify the family and what their problems are? If they find them, can they supply them with the help they need? And is there truly a buried treasure? If so, can they find it before the pirates get it? And will they be able to return safely home to their family?