1 - [s15e17] Underworld

: Stars Tom Baker as the Doctor and Louise Jameson as Leela.

: This episode is available to stream on platforms including BritBox and YouTube TV . [S15E17] Underworld 1

: The Doctor reveals that the Minyans are "old friends" of the Time Lords. Thousands of years ago, Time Lords intervened on Minyos, but the Minyans eventually used the gifted technology for civil war, leading to the Time Lords' strict policy of non-intervention. : Stars Tom Baker as the Doctor and Louise Jameson as Leela

The episode (Season 15, Episode 17) of Classic Doctor Who originally aired on January 7, 1978. In this episode, the Fourth Doctor and Leela land the TARDIS on a spaceship at the edge of the known universe, where they encounter the survivors of the planet Minyos on a 100,000-year quest. Episode Summary Thousands of years ago, Time Lords intervened on

: This story is notable for its heavy use of early blue-screen technology (Chroma Key) to create the vast, cavernous underground settings. "Doctor Who" Underworld: Part One (TV Episode 1978) - IMDb