Classic Who S7 • Serial 3 · (7 episodes)
The Ambassadors of Death
Other variations of this story: The Ambassadors of Death (BBC Audio Soundtrack)
The Third Doctor joins UNIT's investigation of the mystery surrounding Mars Probe 7. Space Control, headed by Professor Ralph Cornish, has had no contact with the astronauts on board since it started back from Mars seven months ago. Now the Recovery 7 rescue mission has run into similar difficulties.
This second ship gets back to Earth, but the astronauts are kidnapped after landing, and Liz Shaw notices that the Geiger counter is at maximum. It transpires that the ship's occupants were not the human astronauts after all but a trio of radiation-dependent alien ambassadors who had swapped places with them.
7 Episodes:
While the Brigadier investigates a loss of contact with Mars Probe 7, the Doctor realises signals coming from the probe are of extra-terrestrial origin.
UNIT retrieve the returned Recovery 7 but then Carrington hijacks it while the Doctor and Liz try to decode the signal he sent.
Carrington is holding the astronauts at a secret location but when he takes the Doctor, Liz and the Brigadier there they find they have been kidnapped.
Liz has been captured by Reegan's men and the Doctor begins to suspect Taltalian is more involved than he appeared.
The Doctor decides to take Recovery 7 back into space to search for the missing astronauts but Reegan sabotages the launch.
The Doctor speaks with the alien captain and learns the astronauts sent to Earth were ambassadors. However, before he can alert the authorities he is kidnapped by Reegan.
Carrington is planning to expose the aliens on live television and call for an interplanetary war and the Brigadier must rescue the Doctor and Liz in time to stop him.