The Doctor, Jamie and Victoria arrive on Telos, where an archaeological group are exploring the Tomb of the Cybermen. But are the Cybermen as dormant as they believe?

The archaeologists learn they are stranded on Telos and Klieg suggests they use the opportunity to explore the Cybermen's tombs.

Klieg attempts to do a deal with the Cybercontroller while the Doctor tries to find a way to refreeze the Cybermen permanently.

The Cybermen have been revived and plan to convert the archeologists into their own kind, prompting Hopper to attempt a rescue.

The TARDIS becomes trapped in space before ending up in an underground station of a mysteriously deserted London.

With Travers having been captured by the Yeti, the Doctor attempts to find a way to gain control of the robots while Lethbridge-Stewart tries to recover the TARDIS.

The Doctor and his friends are held prisoner by the Intelligence and their only hope lies with Jamie, Arnold and a reprogrammed Yeti.

The Doctor discovers the true link between Salamander and Kent while Astrid tries to convince the shelter inhabitants they have been lied to.

Jamie and Victoria are reunited with Travers before Jamie joins the soldiers in attempting to find out what has happened to the Doctor.

Victoria and Travers are held prisoner by the Great Intelligence, who is planning to drain the Doctor's mind.

After the Doctor is attacked by a group of mysterious gunmen, he discovers he is the physical double of the famous scientist Salamander.

The Doctor and Victoria are taken back to the Goodge Street base by Colonel Lethbridge-Stewart where the Doctor becomes convinced there is a traitor in their midst.

The Doctor and Jamie rescue Victoria from Robson and realise they can destroy the Weed Creature with sound waves.

Fariah brings the Doctor and Kent evidence of Salamander's activities but then they come under attack from Benik.

The Doctor persuades Bruce to help him infiltrate Salamander's research centre while Salamander takes drastic action to prevent Swann finding out the truth.

Jamie and Victoria agree to accompany Astrid to Hungary to observe Salamander's activities.

While the Doctor begins his investigation into the weed creatures, Robson is attacked by one at the refinery.

With the Weed Creature poised to burst out of the pipeline and attack the base, an encounter with Oak and Quill gives the Doctor a vital clue about its weakness.

Jamie and Victoria make their way to the monastery shortly before it is attacked by the Yeti.

Jamie and Victoria join Astrid into attempting to rescue Denes but Salamander becomes suspicious of them.

The Doctor, Jamie and Victoria are taken prisoner by the staff of a gas refinery, who have lost contact with their drilling rigs and experienced mysterious drops in pressure.

Harris asks for the Doctor's help with Maggie, while Van Lutyens and the Chief Engineer attempt to find out what is blocking the impeller.

Van Lutyens' investigation of the base of the impeller places the Doctor and Jamie in danger from the Weed Creature.

With the Great Intelligence on the verge of becoming corporeal, the Doctor challenges Padmasambhva to a mental battle in order to defeat it.

The Doctor, Jamie and Victoria are brought to a base which is attempting to halt the flow of the Second Ice Age.