'The Pescatons' (2 Parts) by Victor Pemberton

The Doctor and his companion Sarah Jane battle against some of the most heinous foes to emerge from the outer universe: The Pescatons. The Doctor finds himself in the capital city of London, where the population is bewildered and trembling beneath the violent onslaught of a merciless invader.

Who or what is the mighty Zor, whose green slanting luminous eyes glare out from the dark of night like giant emeralds? What is the powerful alien force that is bringing Earth's civilisation to a standstill, threatening to annihilate everything in its path?

This is the story of a dying Planet, of a Deadly Weed, and the merciless Creatures themselves. It is a Challenge to the Doctor -- a frightening race against time...

Tom Baker (Doctor Who), Elisabeth Sladen (Sarah Jane Smith), Bill Mitchell (Zor)

Directed by Don Norman

Notes:
*Featuring the Fourth Doctor and Sarah Jane Smith

*Audio adventure released on LP and cassette by Argo Records in 1976. Reissued on CD by Silver Screen Records in 1991