The Doctor is behaving very oddly. After signing a treaty with enemy aliens, he returns to his home planet, Gallifrey, and demands the Presidency of the High Council of Time Lords. His first act of rule is to banish Leela to the wastelands on pain of death. His second is to sabotage the planet's defense barriers, enabling full scale invasion. Why has the Doctor joined forces with the militaristic Vardans? Is he out for revenge against the Time Lords?...

When the Doctor and the recently regenerated Romana arrive on a radioactive planet, the Time Lord has the strangest feeling that he has been there before. Exploring the ruins of an old city, it is not long before they discover the disturbing truth. The TARDIS has materialized on Skaro-- original home to the evil Daleks. But who are the mysterious Movellans and what terrible treasure are the Daleks seeking? The answer lies deep beneath the city.