The original PilotEpisode of ''Series/StarTrekTheOriginalSeries''. Written by Creator/GeneRoddenberry and produced in late 1964, it preceded the series itself by a good two years. While this pilot was not considered to have been a success at the time, the network executives did like it enough to finance a second pilot episode. And you all know how well that turned out.
The episode begins with the USS ''Enterprise'' (under the command of Captain Christopher Pike) on a routine patrol. Pike is suffering from self-doubt, having just come from a mission where a number of his landing party were killed in action (including his close friend and Yeoman).
The ship receives an belated S.O.S from survivors of a Earth spaceship that crashed on the nearby planet Talos IV some time ago. Once they arrive on this barren and desolate planet, they find a ragtag bunch of survivors, but something doesn't feel quite right about them. While the landing party does a thorough examination of the group, a young woman named Vina lures Captain Pike to a secluded spot, where he gets zapped by humanoid aliens and taken deep underground.
The survivors vanish, having been revealed to be an illusion created by the alien Talosians. Captain Pike has been placed inside a zoo. The Talosians aim to pair him off with Vina, who is in fact the only true survivor of the earlier spaceship crash. While the aliens use their telepathy to try and bring Pike and Vina closer together, in illusionary versions of his recent near-death encounter, his home city of Mojave back on Earth, and a Orion slave harem; the crew of the ''Enterprise'' attempt to breach the underground complex and rescue their kidnapped captain.
The Talosians finally kidnap two further females from the ''Enterprise'' crew, giving Pike the choice of three potential mates. The ''Enterprise'''s female first officer sets her hand phaser to self destruct, forcing the Talosians' hand and giving them no option but to let the three of them go. Pike watches sadly as the true extent of Vina's injuries are revealed, explaining why she can not come with them.
Footage from this un-aired pilot was later re-edited as a [[Recap/StarTrekS1E11TheMenageriePartI two part]] [[Recap/StarTrekS1E12TheMenageriePartII regular episode]] called "The Menagerie". The original version, however, eventually made its broadcast premiere in 1988, as part of the TV special ''The Star Trek Saga: From One Generation To The Next'', which previewed the writers' strike-delayed second season of ''Series/StarTrekTheNextGeneration''. "The Cage" was also the last of the digitally remastered TOS episodes to air, debuting the week before ''Film/StarTrek'' opened in theaters in 2009.
!!! '''The Cage''' provides examples of the following tropes:
* AbsenteeActor: The entire regular ''Star Trek'' cast except for Creator/LeonardNimoy (and, though in a '' very'' different role, Majel Barrett). Justified in that most of them hadn't even been hired yet.
* AdamAndEvePlot: The Talosians kidnap Captain Pike, and then Number One and a female lieutenant to act as breeding stock.
-->'''Number One:''' "Offspring" as in... he's Adam.
* AllThereInTheManual: A few novels have theorized as to the cause for the vast differences between Spock's highly emotional behaviour in this episode and his reservedness in the regular series. Examples of this include Spock possibly not having complete control of his emotions at that point, as he was still quite young, and that he achieved full control of his emotions by observing Captain Pike. In fact, the novel ''Burning Dreams'' establishes that indeed, whether Pike liked it or not, Spock did consider him a mentor and so Pike tried his best to live up to that assignment. The novel ''The Fire and the Rose'' establishes that Spock was simply emulating Human behaviors such as smiles, and that there was truly no emotion behind his own smile. He eventually stopped though when his crewmates came to distrust him, believing him not to be truthful about himself to them.
* TheBartender: Dr Boyce brings some alcohol with him during his visit to the Pike's quarters, and mixes him a martini as a part of the captain's EpiphanyTherapy.
-->'''Boyce''': Sometimes a man will tell things to his bartender that he'd never tell his doctor.
* BeneathTheMask: Pike's fantasy of being a decadent Orion slave trader.
-->"[[GreenSkinnedSpaceBabe Glistening green]], almost like secret dreams a bored ship captain might have..."
* BlondeBrunetteRedhead: Vina, Number One, and Colt.
* BridgeBunnies: Yeoman Colt; ironically her presence makes Captain Pike uncomfortable as he's not used to having a woman on the bridge.
** Averted and Lampshaded HARD by Number One, who gives Pike a DeathGlare until he leaves the bridge.
* TheChainsOfCommanding: Pike lays out how tired he is of being responsible for the lives of his crew, and making decisions that include "who lives, and who dies".
* CharacterizationMarchesOn: Spock's joyful reaction to hearing the singing plants on Talos IV, and also his panic when he realizes [[MemeticMutation THE WOMEN]] have been kidnapped. Actually, Spock in general.
** According to Nimoy, this was because he felt that Spock needed some warmth to balance out how Hunter played Pike. At this point, Spock was just supposed to be an alien, "probably half Martian". Vulcan heritage and stoicism weren't part of his character yet.
* DespairEventHorizon: The Talosians reach this point with the failure of their plan:
-->'''Captain Pike:''' And that's it. No apologies. You captured one of us, threatened all of us...\\
'''Talosian:''' Your unsuitability has [[DyingRace condemned the Talosian race to eventual death]]. [[ThePunishmentIsTheCrime Is this not sufficient?]]
** Pike's fantasy of being an Orion trader is implied to be this, as he mentioned it during his gripe session with his doctor.
** After beaming Number One and Colt down to Pike's cell as alternate mating choices, the Talosian Magistrate tells him that Number One's IceQueen demeanor is a facade and she's often had fantasies about him, while Yeoman Colt has assumed the captain was [[IgnoredEnamoredUnderling out of her reach]], "but now is [[LockedInARoom realising this has changed]]".
* DirtyOldMan: The doctor pointedly inquires about Colt's impertinent question "Who would have been Eve?"
-->'''Boyce:''' Eve as in...Adam?\\
'''Pike:''' Adam as in All ship's Doctors Are dirty old Men.
* DistressCall: One of these kickstarts the plot.
* TheDulcineaEffect: Pike correctly deduces that the Talosians are trying to make him feel protective of Vina so that he'll fall in love. However, after he points to the illusions that cast her as a DamselInDistress he protests against their treatment of her in the real world, proving that their ploy is indeed working.
* DyingRace: The Talosians. Turns out being able to create illusions indistinguishable from real life but better makes you largely uninterested in real life.
* EarlyInstallmentWeirdness: Everything, from the characters, to the uniforms, to some details of the USS ''Enterprise'' itself.
* EnergyWeapon: The huge laser cannon that gets wheeled out on the planet surface during the ''Enterprise'' crew's attempt to break into the Talos compound.
* EpiphanyTherapy: Dr Boyce's attempts to help Captain Pike get over his HeroicBSOD.
-->'''Boyce:''' A man either lives life as it happens to him, meets it head-on and licks it, or he... turns his back on it and starts to wither away.\\
'''Pike:''' Now you're beginning to talk like a doctor, bartender.\\
'''Boyce:''' Take your choice. We both get the same two kinds of customers-- the living and the dying.
* FacePalm: Vina does this when Pike gets punished for thinking wrong thoughts.
* FateWorseThanDeath: Rather than allow Pike to submit to Talosian captivity, Number One puts her phaser on overload to destroy all three of them. Vina elects not to retreat underground either, since it would mean the Talosians would just grab another man later.
* FieryRedhead: What seems to be implied by Yeoman Colt's "unusually strong female drives."
* FireAndBrimstoneHell: The Talosians can invoke that experience on Pike any time they want as punishment, and threaten to outdo that trauma if they have to.
* GettingCrapPastTheRadar: Yeoman Colt is a suitable mate for her youth, strength and "unusually strong female drives".
* GreenSkinnedSpaceBabe: The TropeCodifier. Although strictly speaking, Vina is only ''pretending'' to be a green skinned space babe. But she's still the first one that we ever see in ''Star Trek''!
* HeroicBSOD: Captain Pike is going through one of these when the episode begins, having lost several crewmen (including his personal yeoman) on a mission.
* HumansAreSpecial: The Talosians desire humans for their adaptability, but then they access the records of the ''Enterprise'' and conclude that humans have "a unique hatred of captivity" that renders them unsuitable for their purpose.
* IceQueen: Number One was designed to be this trope.
* InertialImpalement: How Pike finishes off the barbarian in the illusory battle.
* InMediasRes: The story begins as the ''Enterprise'' has completed a mission that resulted in serious casualties and is returning to base.
* IWillPunishYourFriendForYourFailure: Pike doesn't know Vina and doesn't especially like her, but he objects when she's punished for ''his'' lack of cooperation. This is all part of the Talosians' plan to make him breed with her.
* MasterOfIllusion: The Talosians force Captain Pike to partake in a series of illusionary worlds. When he resists, they are also able to punish him with a FireAndBrimstoneHell and then believably threaten to go deeper into his mind for experiences ''even worse''! Similarly, the Enterprise crew actually easily breaks into the Talosian base, but their powers of illusion made it appear that they'd been doing no damage at all, so they didn't realize they'd succeeded until Pike was already released.
* MovingTheGoalposts: Pike agrees to pick an illusion to share with Vina if she answers his questions. After she does, he says that he made a "bargain with someone that didn't exist" and it doesn't count which forces her to admit that she was lying about being yet another illusion.
* NamedAfterTheirPlanet: Talosians. From Talos IV.
* NoNameGiven: Majel Barrett's character is referred to throughout simply as "Number One".
* PilotEpisode: A failed one, in fact, but it showed enough promise for the network to commission a second pilot.
* PlotHole: Vina claims her misshapen but correctly functioning body is the result of the Talosians having put her back together without ever having seen a human before. But even ignoring the fact that the Talosians themselves are HumanoidAliens with perfect bilateral symmetry along their long axis, ''they could have read her thoughts'' to see what humans looked like.
** Earlier drafts of the episode describe the Talosians as [[StarfishAliens crustaceans]], and the change to humanoids in the final product was a budgetary concession. The telepathy point depends on whether a subject needs to be conscious to have their minds read. It's doubtful Vina was in anything resembling a lucid or communicative state after the crash, considering she herself describes her condition at that point as a "lump of flesh."
** We know the Talosians can't read the mind of someone who's caught up in primal hatred. Possibly the mental state of someone whose body has been mangled in a starship crash is even more primal than that, a frenzy of pain and terror they can't (or possibly don't ''dare'') connect with. Also, who's to say they aren't ''still'' crustaceans, but made themselves look humanoid for convenience during their interaction with Pike?
* PsychicAssistedSuicide: The Talosian Keeper tries to get Pike to release him by threatening to destroy the ''Enterprise''. Vina confirms that he's not bluffing about his capability -- the Talosians' illusion power could reach the orbiting starship and trick the crew into operating the wrong controls -- but it turns out that he's bluffing about his willingness to follow through on the threat.
* PsychicStatic: The Talosians can't read "primitive" emotions like anger or violence.
* RaygunGothic: This episode is where the death of this trope began.
* RecycledInSpace: The start of the ''Literature/HoratioHornblower In Space'' subgenre of sci-fi. Pike's ruminations on choosing which crewmen will live and die are remarkably similar to Hornblower's thoughts on being a Valkyrie "chooser of the slain" in ''Hotspur.''
* RubberForeheadAliens: The Talosians have entire rubber heads. They are more elaborate than later makeups in the series, and they also cast female actors but dubbed over male voices in an attempt to make them more alien.
* SameLanguageDub: Clegg Hoyt played the transporter chief, Pitcairn, but his voice was dubbed in by Bob Johnson.
* SurveillanceAsThePlotDemands: The Talosians seem perfectly capable of seeing everything that goes on in the cell as well as reading minds, but the Keeper doesn't see Pike waiting to ambush him.
* TechnologyMarchesOn: An in-universe example. The consoles on the ''Enterprise'' bridge are here fitted with what look like personal computer printers (which print out messages on paper), and the Yeoman is seen using a clipboard with paper sheets on it. The beam weapons are called lasers instead of the later phasers. And the weapon used in the attempt to blast the Talosian entrance is a bulky device transported from the ship instead of ship mounted weapons. By the time of the series proper, both would be replaced by more futuristic devices. [[spoiler: Medical science is presumably more primitive than it's portrayed in TOS, as Pike doesn't even speculate about the possibility that Vina's disfigurements might be repairable with ''Trek''-era medicine.]]
* TelepathicSpacemen: The Talosians are telepathic, and it's how they create their illusions.
* ThisIsThePartWhere: The Talosians note that, after hurling himself in frustration at the glass, Pike will now threaten then with the power of his starship. Hearing this, Pike chooses a more diplomatic (but equally futile) approach.
* ThrowingYourSwordAlwaysWorks: Pike tries throwing a sword at the barbarian during the illusory battle; it hits at the right angle and with enough force to embed itself in the barbarian's back.
* TooGoodToBeTrue: Pike realizes too late that the heroic survivors they've seen were just playing into their ideal fantasies.
** Between Pike and J.M. Colt in particular. And according to the Talosians, possibly also Number One.
** This was the entire purpose of the Talosians capturing Pike: to get him to develop enough tension with Vina that he would give in and help them breed a new race to reclaim the surface.
* YourMindMakesItReal: According to the Talosians, Pike could visualize the vial of nourishment liquid provided by the Talosians as any meal he wished. Presumably, as long as he was able to somehow forget that it really was nothing more than a vial of blue liquid.