Zeus, a dog owned by Terry Barnett (played by Steve Guttenberg), who is a widower. The lonely man writes music but suffers from writer's block. He is under the care of his son, Jordon (played by Miko Hughes). The dolphin in the tale, Roxanne, is being studied by Mary Beth Dunhill (played by Kathleen Quinlan), a marine biologist. The mother doesn't have a man in her life but has two daughters somewhere between childhood and adolescence.
In the movie the widower and the mother meet in the Caribbean setting when Zeus chases the mother's dog. Zeus and Roxanne meet after the dog stows away aboard the mother's boat. The children wonder if a dog and a dolphin get along, how about a widower and an unattached mother?
The movie is rated PG and has a near drowning, sharks which children might find scary and children who disobey their parents occasionally.