When Zack is given the chance to swim with dolphins on a trip to Florida, he dives right in. But before long, Zack is surprised to find that the dolphins are trying to tell him something ? and even more surprised that he can understand and talk to them! There's definitely something fishy going on here! Could it be genuine animal communication? And can Zack and his new friends get their signals straight and salvage an old sunken ship filled with treasure?