While coping with his parents' separation, eleven-year-old Skeet spends most of spring break in his skiff on a Florida river, where he finds a manatee shot to death and begins looking for the killer.
With their father home from the sea, the rambunctious twins Mokie and Bik make the Bullfrog shipshape for a voyage out to sea, where they make friends with a scaredy-seal, save a runaway boat, and keep track of Waggles.