Parts: 4
Writers: Kit Pedler and Gerry Davis
Airdates: 8 October 1966 - 29 October 1966
Production Code: DD

Doctor: first
Companions: Ben, Polly

Creature Feature: Cybermen

Story: A blizzard heralds the TARDIS crew's arrival at the South Pole, where they come across a military tracking post hidden under the ice. The base crew has noticed a strange force causing an orbital spacecraft to behave oddly, and they soon discover its cause - a planet, moving towards Earth and draining its power.

The Doctor suspects that the planet may be carrying a new form of life, and before long, he is proven correct. The base is approached by a spacecraft manned by tall, robotic beings - not androids, but cybernetically-enhanced humanoids. Cybermen.

The Cybermen are impervious to the cold, and to mercy as well, as they quickly kill several of the base crewmembers. They inform the rest that their planet, Mondas, was Earth's twin. Now running out of energy, it has returned to take Earth's...but that is not all that the Cybermen plan to take. If the Doctor cannot find a way to stop the emotionless creatures, the entire population of Earth will be turned into Cybermen as well. But the Doctor's body is rapidly wearing out, and he may not be up to the task...