London, 1985. The alien mercenary Lytton has been stranded here for nearly a year, but now he has a plan to escape. But how does it involve the Doctor's old enemies - and why are they on Earth at this point in history?

On Telos, the Doctor is reintroduced to the Cyber Leader and meets the Cryons, the planet's original inhabitants who will go to any lengths to get their world back!

The former prison planet Varos, the future. The downtrodden population of miners are kept happy by real-life violence and murder broadcast live from the Punishment Dome. But then the TARDIS materialises inside the Dome...

The Governor forces the Doctor to tell him the true value of zeiton-7 but Sil attempts to derail his plans by subjecting Peri and Areta to an enforced mutation.

England, the 1820s. As the Industrial Revolution gathers pace, the village of Killingworth is disturbed by crazed Luddite miners intent on smashing all machinery and engineers. But is there another cause of the situation?

The Master uses The Rani's mind-controlling parasites to keep a meeting of Earth's leading scientists from being cancelled, and helps her plant transformation land mines for The Doctor, as he continues to propose an alliance with her in ruling over Earth.

The Doctor and Peri meet Jamie and learn the Second Doctor is with the Sontarans on Earth.

The Sontarans prepare the Second Doctor to trigger their Kartz-Reimer capsule.

The planet Karfel, in the distant future. The tyrannical Borad rules with an iron fist, and any who oppose him are cast into the Timelash - a space-time tunnel leading to the past of an alien world called Earth...

The Borad accepts no opposition and enables Maylin Tekker to expose the rebels and trap Peri with the Morlox. The Doctor tries to avert a war between Karfel and the Bandrils.

The planet Necros, the future. The Doctor arrives for the cryogenic interment of an old friend at Tranquil Repose, a vast repository of bodies in suspended animation. But what does the 'Great Healer' really have in mind for them...?

Davros plans to create an army of Daleks loyal only to him but on Skaro, the Daleks have other plans and head to Necros. Caught in the middle of this, the Doctor must save Peri...