In this program, underwater explorer Jacques Cousteau sets out with his crew on the "Calypso" in search of the lost civilization of Atlantis. Writers from Plato to Edgar Cayce have verified the existence of Atlantis and its sudden disappearance beneath the sea. Atlantis was said to be a culture of advanced and peaceable citizens. Is the legend fact or fiction? The viewer goes on-location with Cousteau to discover clues about this now-mythic civilization.