[[quoteright:345:http://static.tvtropes.org/pmwiki/pub/images/gate_2500.jpg]]
[[caption-width-right:350:[[OurTown Here's some scenery, for those that think they need scenery.]]]]
->One good solid hope's worth a cart-load of certainties.
-->-- '''The Doctor'''

The Doctor, Romana, K-9 and Adric are still stuck in [[Recap/DoctorWhoS18E3FullCircle E-Space]]. While they're trying to figure out a way back into N-Space (our universe), the TARDIS is hijacked by a lion-headed HumanoidAlien that walks in through the TARDIS doors ''while the TARDIS is still in flight''. The alien brings the TARDIS to land, announces that his name is Biroc and that they should not trust the people they are about to meet, and departs as mysteriously as he came.

Our heroes find themselves in a featureless white void, empty except for the TARDIS, a stranded spaceship (whose crew, led by Captain Rorvik, are indeed untrustworthy), and an incongruous ruined stone building.

Many confusing things happen. And Adric flips coins a lot.

It turns out that the void is some kind of {{pocket dimension}} that is on (or, perhaps, somehow ''is'') the boundary between N-Space and E-Space. When they eventually find the way out, consequently, our heroes are able to choose which way out to go. The Doctor and Adric return to N-Space in the TARDIS, while Romana and K-9 decide to return to E-Space and help Biroc in his continuing quest.

!!Tropes

* AlmostDeadGuy: "The secret to the gateway is... ''[thud]''"
* AnimatedArmor: The Gundan robots are designed to resemble decorative suits of armor when they're at rest (and are mistaken for such before their true nature is revealed).
* {{BFG}}: Adric holds off the slave traders with their own giant cannon. "I don't know what these levers do...but it's pointing in ''your direction.''"
* BitingTheHandHumor: The privateer crew are, according to JohnNathanTurner, based on Stephen Gallagher's many tribulations while writing at Granada TV, and the poor work ethic he found there.
* DeliberatelyMonochrome: Some of the weirder parts of the story, for thematically-appropriate but difficult-to-summarize reasons.
* DistressedDude: All the Tharils we see prisoner are male.
* FeudalFuture: The Tharils' empire in its heyday.
* GravitySucks
* GreyAndGrayMorality: Between the Privateer crew and the Tharils. Rorvik and his crew have the air of [[PunchClockVillain ordinary people just doing their job]]. Of course, that job is ''slavers'', but as it turns out, the Tharils themselves were slavers of humans in the past.
* HandSignals: Romana tells Adric not to come out if she gives the danger signal...then mimes putting her hands up.
* HumansAreTheRealMonsters
* IChooseToStay: Romana
* IncrediblyLamePun: "You were the noblest Romana of them all." (Compare ''Theatre/JuliusCaesar'' V.v)
* IronicEcho: The weak enslave themselves.
* KilledMidSentence: See AlmostDeadGuy.
* KillerRobot: The Gundan robots.
* KingOfBeasts: The leonine Tharils were once kings.
* MadeASlave
* MeaningfulName: The Tharils are ''thralls'' to the Privateer crew.
* MindScrew: So, imagine you're in a cubby-hole you found behind a mirror, and that hole is in a different universe from the main room. Seriously, don't think about that too long, or [[YourHeadASplode you know what will happen]].
* PocketDimension
* PunchClockVillain: In the worst sense. The privateer slavers think nothing of using the Tharils as ballast. Once they figure out that Romano is "time-sensitive', they immediately stop treating her like a sentient being and toss her into the clink, too.
* [[TheRevolutionWillNotBeCivilized The Revolution Was Not Civilized]]: The reason for the Tharils' plight.
* SheatheYourSword: Doing nothing (Tharils) vs. doing something (Rorvik) becomes an arc over the four episodes. In Rorvik's case, "doing something" resulted in the destruction of his ship and crew.
* SlaveRace: The Tharils, but this wasn't always the case.
* SupernormalBindings: The shackles made from dwarf star alloy, used to prevent the enslaved Tharils slipping away into the timestream.
* ThoseTwoGuys: Aldo and Royce. According to the novelisation, they came with the ship when Rorvik hired it.
* TooDumbToLive: Rorvik
* UsedFuture: The spaceship clearly comes from one.
* VillainousBreakdown: "I'll finally be able to GET SOMETHING DONE!"
* VoidBetweenTheWorlds: The main setting.
* WagTheDirector: Between the esoteric plot, an auteur director, unhappy producers and the two lead actors up in arms, it's a miracle that the script is intelligible. According to director Paul Joyce, who was unprepared for Baker and Ward's feud, "I don't think even TomStoppard or Creator/HaroldPinter could have written a scene that would have satisfied both Tom and Lalla at that point."
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