The eleventh season of Doctor Who saw the end of Jon Pertwee’s tenure on the show, and introduced long-running companion Sarah Jane Smith. The Brigadier and the men of UNIT continued to play a large role in the stories, and more was revealed about the Doctor’s youth, building on the information revealed last season. Also, the Doctor’s home planet finally received a name.
From “The Time Warrior”
Brigadier Lethbridge-Stewart calls in the Doctor when several noted scientists vanish without a trace. The Brigadier has brought together the government’s remaining top scientists in a single complex, where the Doctor meets the young journalist Sarah Jane Smith, who is posing as her virologist aunt. When another scientist disappears, the Doctor traces the transmat beam back to the early middle ages. He follows in the TARDIS only to find that Sarah Jane has stowed away, and discovers the kidnappings are the work of a marooned Sontaran soldier attempting to repair his spacecraft. When the Doctor reveals to him that he is a Time Lord, attempting some intimidation, Commander Linx speculates that Gallifrey would never withstand a Sontaran invasion. At this point in time, Earth apparently has no strategic use in the war between the Sontarans and the Rutans. Linx is killed and the Doctor takes Sarah Jane back to the 1970s.
Sarah Jane Smith was working as a freelance journalist when she used her aunt’s credentials to infiltrate a UNIT operation in search of a story. Stumbling into the TARDIS, she suddenly found herself embroiled in the Doctor’s adventures. It took Sarah Jane some time to settle in to life as a time-traveler and to get used to meeting strange-looking aliens. But the Doctor seemed to very much enjoy her company, and they traveled together for many years, through his third regeneration, before finally parting company as he was about to make his first return to his home planet of Gallifrey.
From “Invasion of the Dinosaurs”
The Doctor and Sarah Jane return to 1973 only to find London has been evacuated, due to the sudden appearance of several dinosaurs shortly after they left, according to the Brigadier. To save Sarah Jane from being evacuated with all the other civilians, the Doctor announces that she is his new assistant. The crisis has been caused by a high-level conspiracy to use a scientist’s experiments to erase the last few million years of history and begin human society again. All concerned are shocked to learn that UNIT captain Mike Yates is part of the conspiracy. Although the scientist is able to begin the experiment, the Doctor proves immune to the time-field’s effects and is able to put a stop to it. Later, the Brigadier says that Captain Yates will be put on extended sick leave and given the chance to resign quietly. The Doctor then attempts to persuade Sarah Jane to join him on an excursion to Floriana in the TARDIS.
From “Death to the Daleks”
En route to Floriana, the TARDIS is pulled off course and “crash lands” on the barren planet Exxilon, its systems completely drained of power. The Doctor uses a hand crank to open the door manually. He and Sarah Jane find a marooned Earth military expedition and a contingent of Daleks who have both come to Exxilon in search of a rare chemical each needs for its own purposes. The Daleks recognize the Doctor as their ancient enemy. To find the source of the power disruption, the Doctor enters an enormous temple, wherein he must pass a series of automated intelligence tests. The Doctor reaches the center of the temple and disables its ancient systems while the human soldiers destroy the Dalek taskforce.
From “The Monster of Peladon”
The Doctor plans a return trip to Peladon, but arrives 50 years later than intended, when the society is embroiled in a Federation war, causing unrest among the lower classes. The Doctor and Sarah Jane quickly get mixed up in local politics, but the people of Peladon unite when a cadre of Ice Warriors arrive and impose martial law. Foiling the Ice Warriors’ scheme brings an end to the war and Sarah Jane seems quite proud of what she and the Doctor accomplished.
From “Planet of the Spiders”
Some time later, in March 1974, the Doctor has been conducting an investigation into psychic phenomena and brings a true clairvoyant, Professor Clegg, to his lab at UNIT headquarters, where he and the Brigadier receive a package from Jo Grant in South America -- the blue crystal from Metebelis III. Meanwhile, Sarah Jane has been working for Metropolitan magazine and she receives a tip from Mike Yates about strange goings-on at a Buddhist retreat where he has been trying to sort himself out after being cashiered out of UNIT. When Clegg looks into the crystal, his mental powers go out of control, allowing a giant spider to materialize in the Buddhist retreat. Clegg is killed by the psychic shock. The spider has come from Metebelis III to retrieve the crystal. To find out what happened, the Doctor also stares into the crystal.
The Brigadier: Never mind the dratted coffee! What about the spiders?
The Doctor: Spiders?
The Brigadier: The ones in the crystal!
The Doctor: Oh yes. You know, Brigadier, when I was a young man, there was an old hermit who lived halfway up a mountain just behind our house. I spent some of the finest hours of my life with that old man.
The Brigadier: What are you talking about?
The Doctor: It was from him I first learnt how to look into my mind.
The Brigadier: The crystal, Doctor!
The Doctor: That’s what I’m trying to tell you, Brigadier. When I looked into that crystal, all I could see was the face of my old teacher.
The crystal is stolen by one of the villains from the monastery, who has merged with the spider creature. They teleport back to Metebelis III, accidentally taking Sarah Jane with them.
The Doctor: Well, there’s only one thing for me to do, Mike. I’ve got to get after her. To Metebelis III.
Yates: In the TARDIS?
The Doctor: Yes, of course.
Yates: But how can you be sure you’ll get there?
The Doctor: Well, the TARDIS may be a little erratic, I’ll admit. After all, she is getting on a bit. But Metebelis III is the one planet I can be absolutely certain of reaching. You see, I wired the co-ordinates into the programmer.
Yates: Yes, but Doctor, a planet’s a big place!
The Doctor: Yes, well, I always leave the actual landing to the TARDIS herself. She’s no fool, you know.
Yates: You speak as if she were alive!
The Doctor: Yes. Yes, I do, don’t I?
Once there, the Doctor and Sarah Jane learn that an Earth colonizing expedition crashed on Metebelis III, whereupon some spiders from the ship were exposed to the native blue crystals which caused them to become large and intelligent. They soon enslaved the surviving humans. Four hundred years later, the spiders intend to invade Earth and conquer it for themselves. However, the invasion must wait until the crystal is off Earth so it cannot be used against them. A spider merges with Sarah Jane before she and the Doctor take the TARDIS back to the monastery, where they meet the mysterious abbot, K’anpo, who seems very familiar to the Doctor.
The Doctor: I know who you are now!
K’anpo: You were always a little slow on the uptake, my boy.
The Doctor: It’s been a long, long time.
Sarah Jane: You know each other?
The Doctor: Oh, yes. He was my teacher My… my guru, if you like. In another time, another place…
K’anpo: Another life.
Sarah Jane: Oh no, don’t tell me you’re a Time Lord, too!
K’anpo: I am. But the discipline they serve was not for me.
The Doctor: No, nor for me.
K’anpo: I wouldn’t have chosen your alternative. To borrow a TARDIS was a little naughty, to say the least.
The Doctor: Yes, well, I had to get away; I hadn’t your power.
K’anpo: Indeed. I regenerated and came to Earth, to Tibet.
Sarah Jane: Regenerated?
The Doctor: Yes. When a Time Lord’s body wears out, he regenerates, becomes new.
K’anpo: That is why we can live such a long time.
K’anpo helps the Doctor realize that he must return the crystal even though doing so means certain death, for the radiation deep in the Cave of Crystal where the leader of the spiders dwells will be more than his body can withstand. The Doctor leaves in the TARDIS for Metebelis III, and K’anpo survives the spiders’ final assault by regenerating. The Doctor descends into the radioactive Cave of Crystal, where the Great One proves to be a spider of gigantic proportions with a terminal case of megalomania. Despite the cellular damage, the Doctor makes it back to the TARDIS. Three weeks after disappearing, he rematerializes in his lab at UNIT headquarters. He collapses to the floor in front of Sarah Jane and the Brigadier. As the Doctor slips into unconsciousness, K’anpo appears as a psychic projection and gives the Doctor’s cells “a little push” before vanishing again, thereby setting in motion the Doctor’s third regeneration.