Doctor Who: 10 Best First Doctor Stories
9. The Keys Of Marinus
As the first of many "quest-based" episodes, this serial revolves around The Doctor, Ian, Barbara and Susan as they split up across multiple different planets in order to find components of the "Conscience of Marinus", a computer that controls justice across the entire planet. Whilst being chased by the Voord, the TARDIS crew scramble across various dangerous locales to find the various keys and avoid being killed by the litany of hostile people/aliens/plants/brains-with-eyes-in-jars that they encounter.
This story has the distinction of being only one of two stories written by Terry Nation that does not feature the Daleks, and the writing talents that made the classic adversaries popular is clearly on display here. With such an adventurous premise, the story makes the most of a relatively tight budget, and the ingenuity on display to realise a variety of locations is nothing short of admirable. Even if the special effects of early '60s television wasn't as impressive as today's standards, one thing that Doctor Who had for the most part was the quality of the writing behind it.
Although the serial may lag in its latter episodes with the trial scenes, the whole premise of The Keys of Marinus was quite ambitious for the early days of the show, and it's a shame that the format was never tried much outside of the classic series. For the most part, this kind of serial was abandoned in favour of the much cheaper and easier to produce four-part serials. Nation himself would reuse the basic idea later on for "The Chase" and "The Daleks' Master Plan" (the latter of which sadly only has three out of its twelve episodes currently in existence). From their introduction, it's also painfully clear that the Voord are the first in an incredibly long line of attempts to try and recreate the appeal of the Daleks (which in this instance, did not work).
An interesting slice of Doctor Who, The Keys of Marinus represents the quality of a show in its early days, regardless of any limitations that may have come about.