"What is it you're really up to, eh? What do you want? You don't want to take over the universe do you? No. You wouldn't know what to do with it beyond shout at it."
The search for the Key to Time takes the Doctor and Romana to Calufrax. The coordinates are right, but it's too warm and inviting a world to be Calufrax. In fact, the world is Zanak. But the Tracer is going berserk—it's sensing the segment everywhere.
It turns out the planet Zanak has been hollowed out and fitted with engines, and is now piloted by the demented Captain - all robotic parts and a nursemaid - who "jumps" it into position around other planets, sucks them dry and mounts the shrivelled husks in a trophy room.
The nursemaid turns out to be the real brains behind the operation, a holographic projection of Zanak's Queen Xanxia, using time dams and the forces generated by the trophy room to remain young. The Captain announced that Zanak's next target is Earth, and the Doctor enlists the help of the native Mentiads to sabotage the engines. The Captain rebels and is killed by Xanxia, who is in turn killed by one of the natives.
The Doctor realises that the segment of the Key to Time he is after is in fact the entire planet Calufrax, now conveniently shrunk to a rather more manageable size...
- Armor-Piercing Question: "Then what's it FOR?"
- Blofeld Ploy: The Captain. "When someone fails me, someone DIES!"
- Even Evil Has Loved Ones: The Captain is very upset by the deaths of his metal death parrot and his favorite Mook, vowing to avenge them.
- Failure Is the Only Option: Failure becomes the only option for the villains in the last episode, when the Captain announces that they intend to consume an Insignificant Little Blue Planet...
- God Save Us From the Queen: Xanxia.
- Ham-to-Ham Combat: The Doctor vs. the Captain.
- He Knows Too Much: Why it is death to enter the mine shafts.
- Hollywood Cyborg: The Captain. Just look at him!
- Incoming Ham: The very first line, in fact.
- Large Ham: The Captain, gloriously so!
- Life Energy
- The Man Behind the Man: Xanxia.
- Mundane Solution: Hit it with a spanner! (albeit telekinetically)
- Not Now, Kiddo: K-9, over and over again.
- Obfuscating Ham: The Captain.
- Pirate Booty: In a very...creative way.
- Pirate Parrot: of DEATH!
- Psychic Powers: The Mentiads, thanks to a shared Hive Mind that uses the Life Energy of the dying worlds Xanax engulfs.
- Space Pirates: In glorious type 2 fashion.
- The Starscream: The Captain.
- Two-Headed Coin: The Doctor uses one to settle a disagreement; it's legal tender from a planet ruled by two kings.
- Walk the Plank
- Wicked Witch: Xanxia doesn't have any magical powers, but her method of keeping herself alive, her real body's withered, decrepit appearance, and her mannerisms all hit the right notes.
- Written-In Infirmity: The Doctor bangs his mouth on the console during the TARDIS' landing, to account for Tom Baker's lisp after being attacked by a dog while filming the previous episode.
- You Have Failed Me...: The Captain's favorite word seems to be "failure," said in varying degrees of pitch and intensity.