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, not least cellular rejuvenation and the use of pacifier guns to alter the mental state of the aggressor.
At the edge of expanding universe, the TARDIS materialises on one of the Minyan ships called the R1C. The Fourth Doctor, Leela and K-9 visit the bridge of the spaceship. The crew of four – 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, however, finally traced the P7E’s signal and head into a nebula to locate the missing ship. In the process the R1C is nearly destroyed, and is almost transformed into 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 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 guards who are in turn responsible to two robots called Seers. In overall control is the Oracle, a powerful super-computer which has shaped the perverse society. Evidently the P7E became trapped in the planet millennia earlier and the entire basis of the mission was lost over time. The Doctor and Leela venture into this perverted society and encounter Idas, a young man nearly killed in a Skyfall, learning how the local population is managed and terrorised. The Seers and Oracle exist in a protected Citadel at the heart of the planetoid (clearly the P7E) and the Doctor, Leela and Idas venture there, in the process rescuing Idas’ father Idmon who was due to be sacrificed to the Oracle. Other slaves are freed too, and flee to the R1C where Jackson makes them welcome. However, the crucial race banks remain in the control of the Oracle. The Doctor, Leela, and Idas venture to the Citadel again to get the precious cargo. However, the Seers have meanwhile captured Herrick and give him what he thinks are the two race banks to take back to his ship. Jackson, Orfe and Tala are overjoyed, little realising that their friend has actually brought fission bombs back to the R1C.
The Doctor has meanwhile made it to the core of the Citadel and confronted the Oracle. He succeeds in locating and stealing the real race banks and then heads off with Leela and Idas to get back to the probe ship. The guards try but fail to defeat their flight. The Doctor gives the real race banks to Jackson, and then takes the fakes out of the craft. Idas takes advantage of the situation to round up the other slaves or Trogs and lead them to the safety of the R1C while the Doctor engineers the fission grenades are returned to the Oracle. With moments to spare, the R1C blasts away, loaded with the slaves and the race banks, and is pushed outward from the planetoid by the explosion of the fission grenades. The TARDIS crew depart, wishing the Minyans well as the journey on to Minyos II, their quest complete.