Altair-4 is a planet populated only by the scientist Morbeus (Walter Pidgeon), his daughter (Anne Francis) and a droid, Robby the Robot. Morbeus' obsession with discovering the secrets of the underground cities of Krel and its long-dead inhabitants have led him to kill his fellow explorers. However, his research is once again threatened with the arrival of another expedition, whose leader (Leslie Nielson) is not deterred by Morbeus' efforts to keep him away from either his adopted home or his daughter. This sci-fi reworking of Shakespeare's 'The Tempest' gained an Oscar nomination for its special effects and has since accrued cult status.