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Which Doctor: Third Doctor
Second Doctor
First Doctor
Companions: Jo Grant
Brigadier Lethbridge Stewart
Sergeant Benton
Allies UNIT
Enemies Omega
Gell Guard
Airdate: 30th December 1972 - 20th January 1973
Writer: Bob Baker and Dave Martin
Director: Lennie Mayne
Previous Episode: The Time Monster
Next Episode: Carnival of Monsters