Jody McGrath, traveling the world with her family on a dolphin research project, struggles to save Twister, her favorite dolphin, from the nets of a tuna boat.
Describes instances of dolphin friendship with humans, dolphin anatomy and life in the sea, care of their young, dolphins as pets and performers, and scientific experiments on their capacity to hear and communicate with one another.
Describes the large sea mammals, related to cattle, sheep, and deer, which are interesting for their intelligence, their gentleness, and their adaptation to the ocean environment.