Let’s get the issues with Frontier in Space out of the way first: much of the story follows the many captures and escapes of the Doctor and Jo; there is a silly, last minute monster added into the final episode; and it’s technically only the first half of a 12 part epic that’s really two 6 part serials.  For some people that is enough to bring this serial down in their eyes, but they’re ignoring just how much writer Malcolm Hulke put into this serial.  This is one of those serials where the alien race of Draconians genuinely feels like a complete culture and the text places them on the same level as humanity, the costumes and makeup being among some of the show’s best creature design.  Hulke lays out a believable conflict exploring humanity’s general tendencies towards xenophobia and how we are manipulated into authoritarianism.

Each capture and escape for the Doctor and Jo serves a purpose, usually to push the pair of them forward to unraveling the mystery pitting two empires on the brink of war.  Hulke takes what he laid down in Colony in Space in terms of where humanity is at and just expands it to give this quite realistic but often depressing picture of how humanity changes but never quite enough.  Having a third party slowly go from Ogrons to the Master to the Daleks is also perfect setup for an all time classic Dalek story (even if this story wraps up all of the plot it needed to and what followed really is a completely unconnected story).  Roger Delgado gives such a great performance as the Master it only adds to the tragedy of his untimely death that this would be his last.  He certainly plays off the Daleks in a more interesting way than Pertwee (who actively disliked working against them).  Paul Bernard is in the director’s chair for the final time and it’s certainly his best looking serial, even if Bernard sometimes favors too many wide shots.  This one is great, often underrated for the overrated story that immediately follows.