Underworld is the fifth serial of the 15th season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts on BBC1 from 7–28 January 1978. In the serial, the crew of an alien Minyan spaceship go on a hundred-thousand-year quest in search of a ship containing a genetic bank that would restore the Minyans' species. Plot In the history of the Time Lords, their involvement with the Minyans of Minyos is regarded as a disaster. The Minyans looked on them as gods but, having learnt much from their science, later expelled the Time Lords, who thereafter adopted a policy of non-intervention. The Minyans resented the Time Lords for their dominion over Minyos. Subsequently, the Minyans engaged in a civil war, using the advanced weapons the Time Lords gave them. In the final conflict, the Minyans destroyed their world. Two ships left Minyos before the final conflict, one carrying the race bank of the Minyans, the other intended to find the race bank and bring the Minyans to a new homeworld - Minyos II. The Minyan civilisation retained some Time Lord gifts, including cellular rejuvenation and the use of pacifier guns to alter the mental state of the aggressor. At the edge of the expanding universe, the TARDIS materialises on a Minyan ship, the R1C. The Fourth Doctor, Leela and K9 visit the bridge of the ship. The crew – Jackson, Herrick, Orfe and Tala – are on a quest (“The Quest is the Quest”) that has taken many millennia and they have rejuvenated many times. Their aim is to find the missing ship, the P7E, which disappeared en route to Minyos II while carrying the genetic race banks of the entire species. They have finally traced the P7E’s signal and head into a spiral nebula to locate the ship. In the process the R1C is nearly destroyed, and is almost transformed into the core of a planetoid as small space rocks are attracted to it. A similar fate actually seems to have happened to the P7E, which is found at the centre of a small planet. The R1C crashes into this planet. Civilisation on the P7E planetoid has taken a curious turn. Most of the population, the Trogs, live as slaves digging rock for fuel and sustenance, but they are culled and killed in rock collapses called Skyfalls. This situation is overseen by