|Publication date||7 December 1978|
Landing on Earth, now a barren, desolate planet, Sarah, Harry and the Fourth Doctor are unaware of the large, watching robot. The robot is the work of Styre, a Sontaran warrior, who uses all humans landing here for his experimental programmes.
What has happened to the other space explorers who have come here?
Why is the Sontaran scout so interested in Earth and is brutally torturing humans, including Sarah Jane? Will The Doctor, be able to prevent an invasion and certain disaster, and save both Earth and his companions?
- Unknown Enemies
- The Experiment
- Mistaken Identities
- The Challenge
- Duel to the Death
- A Surprise and a Triumph
DEVIATIONS FROM TELEVISED STORY