(Hey y'all. Sorry for the delay, moving house, living out of boxes, you know how it is.)
One of the definitive moments for me in John Pertwee's tenure on Doctor Who occurs near the end of "Inferno." After being shunted to a parallel universe where everyone is a fascist (no, not that one) and on which a project running parallel to the one on the Doctor's earth has advanced to critical stage, the Doctor finds out they've inadvertently caused the planet to break apart. Everyone on this earth will die unless they can leave quickly and the Doctor, not really having the TARDIS as a resource, kind of glumly says "I'm sorry, I'm afraid you're all going to die" and then leaves them behind.
Nowadays, these little "Holy shit, the Doctor just got hardcore on these guys" is a pretty standard trope (the new series, especially during David Tennant's "lonely god" era, positively loves it) but at this point in the series' evolution, there really wasn't a moment where the Doctor was faced with an insoluble situation. Oh sure, there's always a body count on Doctor Who, but never something where a whole planet died.
There's little bits like that all through the Third Doctor's tenure, though. Because a lot of underlying Doctor Who mythos got sorted in this period, which when you consider how the whole thing started as a mad scrabble to shore up falling ratings is even more amazing.
At the conclusion of the Second Doctor's run, a few decisions were set in motion, partially because the programme wasn't drawing in the ratings necessary to justify the current approach any longer and Patrick Troughton was on his way out, and so a number of decisions were set in motion.
One, the show would now be in colour. Two, the Doctor would be stranded on Earth. No more hopping in the blue box and buggering off (except when he did) One imagines this was a budgetary decision, accepted in a desire to keep the show going more than it seemed a creatively challenging approach. In fact, they said, rightly, that it limited them two two stories--alien invasion or mad scientist.
Third, and most importantly, the Doctor would be played by Worzel Gummidge, who would play him as a debonair man of action who enjoys old cars, crushed velvet jackets, and karate-chopping people
So they had to try a bit harder to get around all that, and ultimately they succeeded. The Doctor, stranded on Earth, becomes UNIT's (an occasionally-glimpsed cannon fodder squad) scientific advisor and thus, is on hand for the threat du jour, who has plenty of UNIT cannon fodder to wade through whilst the Doctor tries to work it all out.
This bit should have really wrecked the show--one of the Doctor's most appealing traits is that of being an outsider (and more often than not a force for anarchy) and the idea of sticking him in some kind of bureaucracy should have killed the whole thing dead. However, the Doctor is barely an employee and is really just marking time until he can get the TARDIS fixed and blow this Popsicle stand first chance he gets. He frequently finds himself at odds with the Brigadier, most notably when, in the midst of trying to broker a peace deal with the Silurians, the Brigadier says "the hell with them threatening us" and kills every last one of them. The rotating cast of bureaucrats that pop up to meddle with things don't fare much better--in fact, this period of Doctor Who becomes a very anti-establishment establishment show.
That tension carries the show through some ropey and all-too-soon cliche bits. It seems almost inevitable that the latest government science project or space mission or new power plant is bound to either contain a Terrible Secret or tampering in things Man Was Not Meant To Meddle In, and after awhile that gets a bit old. One begins to fear imminent catastrophe every time someone digs a hole in the ground.
Thankfully, this is where The Master comes in.
It wasn't like they hadn't done evil Time Lords before--the First Doctor had The Monk and the Second Doctor had the War Chief, but they were either comedic figures or one-shot baddies. The Master in a whole different class. He's basically The Doctor, only evil (and a bit camp, not that you need me to tell you that) Their interplay disguises a lot of the samey bits and evil corporations and alien invasions that sometimes threaten to weigh the damn show down at times, and it injects a lot of joie de vivre into the proceedings.
Witness this clip from "The Sea Devils." It's pretty much everything awesome about the Third Doctor in two minutes:
I have no idea why they locked The Master up with a bunch of swords and guns and shit, but these are the little lapses you just learn to go along with when it comes to Doctor Who.
Oh yeah, and to celebrate the shows first decade, all three Doctors unite to battle another rogue Time Lord (well, actually Two and Three do everything, One just kinda sits in a triangle and points them in the right direction from time to time) in one of those great dream stories that kinda falls short but you don't care because holy shit all three Doctors together (It's kind of a standard thing--whenever you see characters who never mix usually, there's a certain rush that strikes you--fans of Ultraman and Kamen Rider have an idea of what this is like, and if comics hadn't so neutered the idea of crossover, you'd get that feeling in comics too) It also establishes the trope that whenever the Doctors get together, they tend to bicker a lot (we'll bring that up seven parts from now) the episode is a bit slight, but you're not really watching it for the plot as much as you are the event.
Another bit they kinda picked up and dropped was the Third Doctor having romantic feelings (no, RTD, didn't pull this out of his ass when the show returned in 2005) for his second companion, Jo Grant. To be fair, this really doesn't come to a head until her final story, "The Green Death" (subtlety has nothing to do with Doctor Who titles) wherein she runs off an marries the head of some damn hippie commune "who seems very much like the Doctor" and the Doctor gets all sombre and leaves it's underplayed and just as well, because it's kinda . . .icky. I mean, he's several orders of magnitude her age.
Anyways, by the time of the Third Doctor's final season, he's back traveling through time and space again, and he's picked up Sarah Jane Smith, who becomes one of the most enduring companions in the shows history (seriously, she got her own spinoff twice over, for God's sake) the Daleks have returned ("final end," my arse) and the Doctor is tooling around in a rather sharp-looking flying saucer.
And it's about here things change once again, as Number Three has a run-in with some spiders (they are very big spiders, in his defence) and, as the Brigadier says, "here we go again."
Join us next time when the Doctor goes all "teeth & curls" and the running of Doctor Who after Mister Rogers' Neighborhood warps a young child/future blog writer in a small North Carolina town for all time. Tons have been said about Tom Baker as the Fourth Doctor, so please stay tuned for even more of that. I would totally be your best friend if you did.