Parts: 6
Writers: Brian Hayles, Terrance Dicks (parts 3 - 6)
Airdates: 25 January 1969 - 1 March 1969
Production Code: XX

Doctor: second
Companions: Jamie, Zoe

Creature Feature: Ice Warriors

Story: The TARDIS lands in a museum dedicated to the progress of space flight. The owner, Professor Eldred, is initially suspicious of the time travellers, but eventually warms to the Doctor, thanks to his interest in the exhibits. Eldred tells them that space travel has practically been abandoned since the invention of Travelmat, or T-mat, a device that can transport people around the world and to the moon in the blink of an eye.

But the people in charge of T-mat are having difficulties with their supposedly infallible system. The station on the moon has lost contact with the Earth, leaving them no option but to use one of Eldred's antiquated rockets to send a repair crew - the Doctor, Jamie and Zoe. But when they arrive, they discover that the moon station's problems are more than technical - the station has been invaded by the Ice Warriors.

The Ice Warriors use T-mat to release a Martian fungus in the Earth's northern hemisphere. Rapidly growing and spreading along the countryside, the fungus will deplete the Earth's oxygen supply, leaving the planet suitable for colonization by the Ice Warriors. The Doctor, Jamie and Zoe have little time to free the moon base from the Ice Warriors and rid the Earth of the fungal infestation before an invasion fleet will arrive to take over the entire planet...