The code refers to Part Two of the 1978 Doctor Who serial titled " Underworld ". This episode is the 18th in the show's 15th season and features the Fourth Doctor, played by Tom Baker. Plot Overview
: The society is controlled by "The Seers," who value radioactive energy over human life. [S15E18] Underworld 2
: This serial is notorious for its heavy use of Color Space Overlay (CSO) , a primitive green-screen technique, to create the cave settings. Reviewers from IMDb note that while the lasers and some CSO effects work, others look "simply awful". The code refers to Part Two of the
: Critics generally find Part Two to be the weakest segment, describing it as "extremely dull" with roughly 20 minutes of "walking around and gas". : This serial is notorious for its heavy
Reports on the episode's quality are mixed, often highlighting the ambitious story vs. the limited production budget of the time:
In this chapter of the four-part story, the Doctor and his companions explore a slave-labor mining society on a newly formed planet.
: You can find this classic episode on streaming platforms like Apple TV or Tubi .