The Trial of a Time Lord: Part Two 1986
6.8 218 The Doctor finds that the subterranean UK Habitat is run by a cloistered robot named Drathro, whom the inhabitants call "The Immortal." Their black light energy converters are destabilizing, unaware that it's the result of two space pirates mucking about on the surface with designs on looting their dwelling.
Runtime: 25
Starts: Colin Baker, Nicola Bryant, Michael Jayston, Lynda Bellingham, Joan Sims
Director: Nicholas Mallett