Twelve-year old Dusty is terrified of drowning. He'll make any excuse and even lie to get out of getting in water. Matters get even worse when his father marries a woman with two daughters, all of whom love living on Galveston beach and swimming everyday. His excuses are genius, but he can't get out of a Caribbean cruise with his new family. Things are going badly until Dusty hears someone crying in the cabin next door, Cabin 102. It is a girl named Tahni. Could she be the ghost of an Arawak Indian who died in a hurricane on a Spanish galleon in 1511? Through Tahni's friendship, Dusty gradually leans to accept swimming. In the climactic ending he must face the worst of his fears if he is going to save his family and return Tahni to her beloved island home.