Michael Larson, a marine research scientist and his two kids are transplanted down under to study dolphin communication; when trouble arises, dolphins come to the rescue. David Larson is the teen-age son who, angry about the move, has the usual trouble at school; Katie Larson is the sister who hasn't spoken since their mother's death, of course, she's able to mysteriously communicate with the dolphins.
Michael distrusts an old buddy who wants him to join a radical enviromentalist group.