The Doctor and Romana learn the second segment of the Key to Time is on the planet Calufrax. Yet they arrive on a planet called Zanak, which has been hollowed out and fitted with hyperspace engines, allowing its insane, half-robot Captain to materialise it around smaller planets and plunder their resources.
Tom Baker , Mary Tamm , John Leeson , Bruce Purchase , Rosalind Lloyd , David Sibley , Ralph Michael
BBC
