The Cybermen are hiding in the London sewers and turning humans into semi-cybernetic slaves.
On Telos the Doctor is reintroduced to the Cyber Leader and meets the Cryons, the planet's original inhabitants.
Needing Zeiton 7 ore urgently for the TARDIS, the Doctor takes Peri to Varos.
Sil has negotiated to own all mining rights on Varos, depriving the Doctor of what he needs.
The village of Killingworth is disturbed by crazed miners intent on smashing all machinery and engineers
The Doctor fights to stop the changing history. With the Rani on his side, the Master may be impossible to beat.
The alien space station J7 comes under attack from the Sontarans where there are experiments into time travel.
The Doctor follows the trail to the outskirts of Seville, where a monstrous experiment is about to begin.
The evil Chessene puts in motion her plan to acquire the power of time travel.
As rebellion grows on Karfel, the Maylin's daughter Vena falls into the timelash while protecting a rebel.
The Borad accepts no opposition and enables Maylin Tekker to expose the rebels and trap Peri with the Morlox.
The Doctor and Peri arrive on Necros to attend the funeral of an old friend of the Doctor who has recently died.
Davros plans to create an army of Daleks loyal to him but the Daleks have other plans.