Synopsis: The Doctor and his companions land on the planet Marinus. There they find a large tower, and after navigating its secret entrances, the group finds an man named Arbitan, Keeper of the Conscience of Marinus, a vast computer developed two millennia earlier as a vast justice machine which kept law and order across the entire planet by eliminating all thought of evil. But then Yartek, leader of the alien Voord, worked out how to resist its impulses. Inspired by Yartek, the Voord are seeking to enter the tower and take control of the Conscience.
Arbitan explains that the Conscience has now been upgraded sufficiently to control the Voord again, but needs to be activated. Years earlier Arbitan had prevented the Conscience from falling into Voord control by separating the five Keys needed to regulate it, four of which are spread out at different locations on Marinus. The keys can only be found by following directions pre-set into travel dials, watch-like devices with the power to transport the wearer across the planet to the correct locations. Arbitan asks that the Doctor and his friends help him fend off the Voord by gathering the keys together. Others have tried to accomplish this task – even Arbitan’s own daughter – but none have returned to the tower.
The Doctor refuses Arbitan’s request, but is unable to access the TARDIS due to a force field Arbitan places around the ship. And so the Doctor and his companions are coerced into aiding Arbitan. As the four teleport away from the tower using the travel dials, Arbitan is attacked and stabbed to death by a Voord that has secretly gained access to the tower.
Their first destination, Morphoton, proves to be a challenge, but Barbara ends up saving the day. In order to retrieve the keys, the group (which now includes two of the people that Arbitan sent out for the keys orignally) decide to split up in order to find the keys faster.
After many adventures, the group returns to Arbitan’s island with the four other keys. They do not know the old Keeper is dead and that Yartek is now in charge, clothed in Arbitan’s robes to maintain the ruse. Yartek has seized the first four Keys and holds Altos and Sabetha prisoner while he awaits the fifth and final one. When the Doctor and his three friends arrive they soon realize that the Voord have taken control of the tower and the Conscience. The Doctor frees Sabetha and Altos and then unmasks the Voord. Ian too has played his part, and given Yartek the false key from the Screaming Jungle. When Yartek places the false Key in the Conscience, the machine explodes and he is killed along with the occupying Voord. The Doctor and his friends flee the tower with Altos and Sabetha before the growing blaze overtakes the ancient structure. (synopsis modified from Wikipedia)
Importance: There are a couple episodes in this serial that the Doctor doesn’t appear in. This then shows the resourcefulness of his companions as they find themselves having to navigate dangerous situations without him. Other than this, however, there isn’t much to this serial.
Thoughts: I did like that there were two episodes in the serial that the Doctor was not in. This allowed us to see the companions making their own way, and really demonstrated just how capable they are. However, I did find Susan a little useless in the majority of this story. Most of the spotlight was on the ingenuity on Ian and Barbara. Seriously, they would all be dead ten times over without those two.
This was an especially good story for Barbara, since she saves the day in the second episode single-handedly. Barbara has really grown since the series started, and the respect that the Doctor has for is well-placed and well-earned. Barbara has proven herself time and time again, and these episodes are no exception.
However, other than this, I didn’t find this serial to be overly exciting. I found myself wanting to do something else as I was watching, and actually started working on crocheting a hat.
The main concept of a machine the suppresses violent urges through an entire populace is interesting, but it is so secondary that you actually sometimes forget what that machine does. There was a lot of potential for some philosophical examination as to the morality of this machine, but it’s simply not there. It’s a little disappointing.
Of course, according to the Wikipedia page (which I linked above) this story was a rush job, since the original script didn’t pan out. So it’s understandable that it doesn’t seem as well thought out as many of the other episodes.
Watch it?: You could probably safely skip these episodes. Nothing important happens that I believe is important to the grand scheme of Doctor Who. It’s just kind of a one-off story that’s just there.