The Doctor is captured by the Daleks, while Jo is rescued by a friendly Spridon named Wester.

The Doctor and Codal escape from their cell and meet up with the Thal commandos who are trying to get into the Dalek base.

The Doctor and his friends escape from the Dalek base, prompting the Daleks to devise a plan to wipe them out.

The Doctor and his friends ambush two Daleks as part of their plan to get back into the city, but the Daleks are on the verge of unleashing their virus.

The Doctor and his friends prepare to refreeze the Dalek army but the Dalek Supreme has arrived on the planet determined to destroy them all.

The barren planet Exxilon, some time in the future. The TARDIS is forced down by a total power failure and the Doctor and Sarah meet a stranded Earth crew who came here to mine for priceless medical supplies. But what is causing the power failures? And why have the Daleks come here too?

The Doctor and the MSC crew join forces with the Daleks to mine the parrinium, only to come under attack from the Exxilons.

The Doctor and Sarah meet up with Bellal, who helps them escape from the Daleks and explains the origin of the City.

The Doctor and Bellal continue to penetrate the City's defences while Sarah and Jill try to stop the Daleks leaving with the parrinium.