The Seeds of Death

It is the 21st Century and Earth is totally dependent on T-Mat, a revolutionary form of instant travel. When the system breaks down the Doctor and friends make a hazardous journey to the relay station on the moon only to find that it has fallen into the hands of the Ice Warriors who plan to invade Earth.

Using T-Mat, the Ice Warriors transport seed pods to Earth which burst, disgorging a deadly Martian fungus. This spreads rapidly, extracting vital oxygen from the atmosphere. Can the Doctor outwit the evil Ice Warriors and destroy the fungus in time to save a dying world?