The Doctor and Jo arrive on the medieval planet Peladon, where the Doctor is mistaken for the Earth Delegate of the Galactic Federation and Jo is mistaken for a princess.

The Doctor is convinced the Ice Warriors are trying to sabotage the conference but his attempts to prove it see him accused of sacrilege.

The Doctor is sentenced to fight Grun to the death and his attempt to escape leads to an encounter with Aggedor.

Hepesh's plan has been exposed but he is still determined to prevent Peladon joining the Galactic Federation by leading a rebellion against the King.

England, the near future. A strange anti-matter creature arrives on Earth and attacks UNIT HQ. It seems to be specifically seeking the Doctor out - but why? With the Time Lords themselves unable to help, it seems the only person who can help the Doctor is himself - or selves...

The third Doctor and Jo find themselves on an artificial world inside the black hole while the second Doctor tries to find a way to control the organism.

The Time Lord Omega reveals himself to the third Doctor along with plans for vengeance against his own kind.

Omega reveals the purpose behind bringing the Doctor to his antimatter world, but the Doctor(s) discover a startling fact about Omega that he didn't know himself and eventually strike a bargain.

The planet Peladon, some time in the future. Mining disputes threaten the peace of the planet, and as the Doctor and Jo arrive, it seems that the ghost of Aggedor walks once more...

The Doctor is rescued by Gebek, prompting him to try and help the miners, but his advice results in Ettis launching another attack on the armoury.

The Doctor and Sarah pacify Aggedor and the Doctor encourages the Queen to make peace with the miners, but Ortron soon has him under arrest again.

The Ice Warriors take control of the planet and force the miners to return to work but Ettis takes the opportunity to try and destroy the citadel.

Sarah and Alpha Centauri decide to try and alert the Federation to what the Ice Warriors are up to but first they have to escape from the throne room.

The Doctor turns the Aggedor spirit against the Ice Warriors to aid the Peladonians in their battle but Eckersley attacks him with the security system.

England, the near future. The TARDIS materialises in a quarry and Sarah is trapped under a rockfall. But what is the origin of the fossilised hand she is found gripping ? And who is the Eldrad she keeps mumbling about ?

The Doctor and Professor Watson struggle to stop first Sarah Jane and then Driscoll from obeying the strange and dangerous orders of the stone hand, which has suddenly come to life.

The energy of the reactor has returned the mysterious Eldrad to life. The Doctor agrees to take her back to Kastria. But what is waiting for them there?

The Doctor and Sarah race to save the mortally wounded Eldrad. But they find that everything is not quite as she told them.