%% Image selected per Image Pickin' thread: https://tvtropes.org/pmwiki/posts.php?discussion=1612595924008204900
%% Please do not replace or remove without starting a new thread.
%%
[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/rsz_turnaboutintruderhd13181.png]]
[[caption-width-right:350:It's finally happened -- the power of Shatner's ham has manifested as a spiritual force.]]
%%

'''Original air date:''' June 3, 1969

The last episode of the original ''Star Trek'' series. It's known for being the most overtly sexist episode of the show and certainly not a worthy SeriesFinale, and many fans prefer to think of the previous episode, "[[{{Recap/StarTrekS3E23AllOurYesterdays}} All Our Yesterdays]]", as the true finale. Of course at that time an episode intended as a series finale was quite rare. But hey, it's not the last we'll be hearing from these characters.

Alternatively, you may regard it as the ''Star Trek'' version of ''Literature/FreakyFriday''.

The ''Enterprise'' goes to some planet to rescue the two survivors of a doomed archaeological expedition. Dr. Arthur Coleman seems to be fine, but Dr. Janice Lester is unconscious. (One wonders if the writers forgot there used to be another "Janice" on this show or if they averted OneSteveLimit on purpose.) Shock of shocks, Dr. Lester turns out to be an ex-girlfriend of Kirk. After Kirk is left alone with her, she comes to and they chat about olden times. It becomes apparent that they had some serious BelligerentSexualTension going on back in the day.

And then Lester says a line. Among Trekkies, the meaning of this line is as hotly contested as the meaning of the [[UsefulNotes/AmericanGunPolitics Second Amendment]] in the US.

->'''Lester:''' Your world of starship captains doesn't admit women. It isn't fair.\\
'''Kirk:''' No, it isn't.

* A popular alternative reading is that it refers to Kirk being unable to carry on his relationship with her after he became captain of the ''Enterprise''. This does make sense within the context of this scene, but makes the rest of the episode somewhat nonsensical.
* The offical {{Retcon}} from Creator/{{Paramount}} seems to be that Lester is just insane, which is very much supported by the rest of the episode; and she deludedly believes she was barred from command because of her gender when it was because of her instability.
** This does raise the question of why Kirk agreed with her. Given that she's an old flame who went crazy when ''she'' didn't become a captain, the answer might be subtextual: he's not agreeing with her, but rather saying her mental illness and delusions are "not fair"; she did not deserve this fate. He chooses to be ambiguous in order to tactfully avoid arguing with her. Or Kirk ''thought'' she meant the first one, [[OneDialogueTwoConversations and was agreeing to that statement, when she was actually just talking crazy-talk]].
* Leonard Nimoy stated flatly and unequivocally in interviews that Gene Roddenberry intended for this to mean women can't be captains. There's no reason not to believe this given Gene's attitude at the time. Nichelle Nichols revealed that a scene in which Uhura took the helm (as she'd done in a couple of first season episodes) was rewritten so that she didn't. Nichols furiously "pitched a bitch" at Gene and got told "You can't have females running a man's ship."

In any case, the idea that women can't be starship captains is [[CanonDiscontinuity never mentioned again]], a female starship captain was seen in ''Star Trek IV'', there was later [[Series/StarTrekVoyager an entire series about one]], and both ''[[Series/StarTrekEnterprise Enterprise]]'' and ''[[Series/StarTrekDiscovery Discovery]]'' featured female captains ''predating'' this episode.

Janice Lester plugs Kirk into an ancient machine which causes a FreakyFridayFlip. Now in Kirk's body, Lester quickly reveals herself to be AxCrazy, supplying us with some of [[EvilIsHammy Shatner's trademark evil acting]]. Meanwhile, Lester's body is unconscious once more. Lester-in-Kirk prepares to kill Kirk-in-Lester, but the rest of the landing party walks in at the wrong moment. Lester, of course, pretends to be Kirk, beginning a TyrantTakesTheHelm plot. In Sickbay, Lester-in-Kirk meets with Dr. Coleman, with whom she is in cahoots. It's revealed that Lester murdered her expedition and Coleman was a willing accomplice. After [=McCoy=] and a suddenly brunette Nurse Chapel arrive, Lester-in-Kirk announces that Kirk-in-Lester is being placed under the care of Dr. Coleman. [=McCoy=] protests that this violates Starfleet protocol since he is Chief Medical Officer, but Lester-in-Kirk ignores this. By the way, Lester-in-Kirk frankly talks about her scheme in {{Captains Log}}s. Does no one ever actually read those things? Even weirder, later we hear Kirk-in-Lester do the log, which makes even less sense.

After an escape attempt, Kirk-in-Lester is placed in solitary confinement. Spock visits and Kirk-in-Lester explains what happened. Spock performs a Vulcan mind meld (or at least a mind touch), which convinces him, but he notes that it won't count for anything in the way of evidence. [[note]]Evidence obtained by telepathy is inadmissible in court because it's considered hearsay. Apparently this is still true in the 23rd Century. And Vulcans can absolutely lie, given a logical reason to do so. . . though what a "logical reason" would be in this case is unclear.[[/note]] Spock tries to help Kirk-in-Lester escape, but they're caught and Lester-in-Kirk has Spock charged with mutiny. At a court martial, Spock states his case. Kirk-in-Lester is then questioned in a very condescending, chauvinistic manner by Lester-in-Kirk. When Spock refuses to drop his charges, Lester-in-Kirk has a VillainousBreakdown and goes into a yelling tirade. Her new favorite word is "mutiny".

During a recess, [=McCoy=] and Scotty discuss the fact that Kirk is NotHimself and agree they'll have to move against him. This becomes an EngineeredPublicConfession, as the corridor was bugged (rare surveillance competence from Starfleet). Lester-in-Kirk decides she has the authority to pronounce a sentence of death for Spock, [=McCoy=], and Scotty. Sulu and Chekov point out the death penalty is reserved for General Order 4[[note]]They probably meant [[Recap/StarTrekS1E11TheMenageriePartI General Order 7]].[[/note]], but the {{Red Shirt}}s are totes okay with this. When Lester-in-Kirk is back on the bridge, she and Kirk's essences briefly switch places again. Realizing the transfer is weakening, Lester-in-Kirk goes to Coleman and tells him to kill Kirk-in-Lester to ensure she won't go back into her own body. They set off to collect Kirk-in-Lester from the brig, but a scuffle ensues. In the midst of it, Kirk and Lester's essences slid back into their own bodies permanently.

The episode wraps up with an AlasPoorVillain ending, in which we learn Coleman was in love with Lester. (So he helped the woman he was in love with turn into a man? [[IWantMyBelovedToBeHappy That could say a couple]] [[HoYay of things about him.]]) Kirk delivers the last line of the series: "Her life could have been as rich as any woman's, if only... if only..." The meaning of this line is debated almost as much as the one from earlier. Does "if only" mean "if only she kept to her proper gender role" or "if only society hadn't forced her into a gender role she hated"? Or both, perhaps? Make up your own mind.

This episode's title is a play on the title of ''Film/{{Turnabout}}'', a Creator/ThorneSmith body swap comedy about a husband and wife. For many years, it was a popular bit of ''Star Trek'' trivia that Sandra Smith (Dr. Lester) was the only person other than Creator/WilliamShatner to officially portray Captain Kirk. This remained true [[Film/StarTrek2009 until 2009]]. In the world of fanfiction, Dr. Lester would find a niche in SlashFic, her story providing a canon setup for JumpingTheGenderBarrier. Slashers have also had a lot of fun imagining what Spock saw during that telepathic contact to convince him Kirk was in Lester's body.

----
!!Turnabout Tropes:

* AmbiguousGenderIdentity: Lester vehemently hates being a woman, calling it ''an indignity'' and enjoying getting physically handy with Kirk when the ''tables are turned'' as it were. Whilst the case is pretty good for her secretly being trans, the argument is there for her also being gender fluid, as when she ended up in Kirk's body she continued to perform stereotypical female acts such as filing her nails. Needless to say, we weren't going to get the answers on a show made in the 1960s.
* AntiMutiny: Slowly the entire bridge staff turns against Lester-in-Kirk. First Spock believes Kirk when he telepathically discovers he's telling the truth. Then during Spock's mutiny court-martial [=McCoy=] and Scotty conspire (albeit reluctantly) to take over the ship as "Kirk" has clearly gone mad and is unfit to command the ship. Then Chekov and Sulu, both horrified at "Kirk"'s actions, just stop following Lester-in-Kirk's orders and ignore her.
* AxCrazy: Lester.
* BackAlleyDoctor: Coleman was drummed out of Starfleet Medical for dangerous incompetence.
* BrokenAesop: If you can call [[StayInTheKitchen what the episode was trying to say]] "AnAesop." Janice Lester blows her chance at command not because she's a woman -- which, having transferred her consciousness into Kirk's body, she's now 100% biologically male -- but because she's pants-on-head crazy (or skirt-on-head crazy, if you prefer). Gender and sexual identity in reality are certainly a lot more complicated than simple binary biology, but the "message" still comes out less as "women make bad captains" and more as "[[CaptainObviousAesop complete raving lunatics make bad captains]]."
* ContinuityNod: Kirk (while in Lester's body) recalls the events of "The Empath" and "The Tholian Web" to Spock. Additionally, Sulu outright cites General Order Four from "The Menagerie" after Lester-In-Kirk orders that Spock, [=McCoy=], Scotty, and Kirk-in-Lester be executed.[[note]]The Federation only has ''one'' crime for which the death penalty is legal: Unsanctioned visits to [[Recap/StarTrekS1E0TheCage Talos IV]].[[/note]]
* DamnYouMuscleMemory: While in Kirk's body, Lester is obviously uncomfortable having a ShirtlessScene, holding up their command shirt over the chest area.
* DeadpanSnarker: Spock, mostly just to rile up Lester-in-Kirk.
-->'''Spock''': May I point out....'Captain'...
* DeusExMachina: The transference happens to break just when it's time for the episode to wrap up. The weird part is that it seems entirely unnecessary. Since the crew was already in mutiny, it's easy to imagine the episode could have ended with them overthrowing Lester-in-Kirk, returning to Camus II, and swapping the bodies back.
** Spock likely weakened it deliberately via another mind-meld.
* DiagnosisKnowingTooMuch: Lester-in-Kirk tries to do this to Kirk-in-Lester, as "Lester" (or at least what the crew ''thinks'' is Lester) already has had a history of mental instability, and "her" claims, that "she" is actually a body-swapped Captain Kirk, might fall on deaf ears as mad ravings. Unfortunately, Lester-in-Kirk takes the false act that her former body is dangerous too far (by knocking Kirk-in-Lester unconscious when "he" is already up and about, but is unarmed and has no intention to attack or harm anyone), alerting Spock and [=McCoy=] to a disparity.
* DidntThinkThisThrough: Lester pitches a huge fit when one of her orders is questioned... '''because it goes against Starfleet law'''. Did she really think that being a starship captain would make her some kind of untouchable dictator, or consider that even captains have to answer to someone?
* EarlyInstallmentWeirdness: Despite being the last episode in the Original Series, the episode's apparent sexism regarding women not being captains is this for the rest of the franchise, given the numerous female captains which have turned up in both films and spin-offs - even those set ''before'' [=TOS=].
* FemaleMisogynist: According to Kirk, Lester feels "intense hatred of her own womanhood." At the start of the episode, Lester herself speaks of "the indignity of being a woman," and declares that, "it’s better to be dead than to live alone in the body of a woman."
* FreakyFridayFlip: Kirk and Lester's bodies are swapped.
* FutureSocietyPresentValues: It's revealed (maybe—see above) that ''women aren't allowed to be captains in Starfleet,'' in the 23rd century. A female character who tries to get around this rule by using alien technology to switch bodies with Kirk is portrayed as being a horribly misguided fanatic.
* GenderBender: Kirk's mind is moved into a woman's body, and her mind is moved into his.
* GrandTheftMe: Lester steals Kirk's body.
* InsistentTerminology:
-->'''Lester-in-Kirk:''' You claim that, that you are Captain James T. Kirk?\\
'''Kirk-in-Lester:''' No. I am not Captain Kirk. That is very apparent. I claim that whatever it is that makes James Kirk a living being special to himself is being held here in this body.\\
'''Lester-in-Kirk:''' Oh. However, as I understand it, I am Dr. Janice Lester.\\
'''Kirk-in-Lester:''' That's very clever, but I didn't say it. I said, the body of James Kirk is being used by Dr. Janice Lester.\\
'''Lester-in-Kirk:''' A subtlety that somehow escapes me.
* JustFollowingOrders: All of the security guards shown don't seem to have any objections to what Lester-in-Kirk tells them to do, even if it means executing the First Officer, Chief Engineer and Chief Medical Officer.
* KangarooCourt: Lester-in-Kirk holds a show trial to shut Spock up for good. It backfires on her spectacularly.
* KarmaHoudini: The episode ends with a crying Dr. Lester being escorted to Sickbay while everyone feels sorry for her. It's possible that she (and Coleman) were later punished for their actions, which include mass murder, but it's certainly not shown or even implied.
* LargeHam: This episode possibly has Shatner at his ''hammiest'', which is really saying quite a bit. On the other hand, his performance as Lester-In-Kirk, and steady emotional collapse throughout the episode is ''quite'' convincing evidence that Shatner isn't given enough credit as an actor.
* MakeItLookLikeAnAccident: Dr. Coleman sends his staff into a dangerously radioactive location, then feigns ignorance as to the cause of their illness and eventual death, thus getting away with multiple murders.
* ManIFeelLikeAWoman: Inverted, as while Lester might hate Kirk, she still gropes his abs and jawline.
* OutOfCharacterAlert: For numerous things, actually. First, "Kirk" hits "Lester" hard enough to knock her down. Then he disintegrates into screaming hysterically at Spock and accusing him of mutiny. When he orders the "traitors" executed, it completely cements the suspicion in every officer's mind. Sulu and Chekov flat out refuse to follow his orders after that pronouncement. Scotty even tells [=McCoy=] while trying to convince him to side with Spock that he has seen Captain Kirk in all sorts of moods, but never "red-faced with hysteria".
* PlotHole:
** Not counting the ones listed in the summary, there's one that became famous due to being cited in the book ''Star Trek Lives'' - at one point, Kirk leaves the bridge ''going the wrong way''. (The door is in the opposite direction.) When the episode was filmed, Shatner joked with the director about how, even if it's the last episode, there was no need to throw Kirk into the vacuum of space, and then tried to have the blocking changed (unsuccessfully, though he did accurately predict that the fans would notice).
** Also, during the hearing, the crew did not think to try the age old trick of asking Kirk/Lester and Lester/Kirk questions that only the real Kirk should know the answer to. It wasn't enough for Kirk in Lester's body to know about their episode with the Tholians and the Vians (Spock points out that both incidents were on record so Janice could have looked them up). But it was enough to convince Spock to make telepathic contact and discover the truth. What is never explained is how Lester in Kirk's body could have access to all of Kirk's personal authorization codes and passwords, things that are likely solely memorized and never kept anywhere written down and probably changed frequently. Without this sort of info, her plan couldn't have succeeded for long.
** Before taking over Kirk's body, Lester was the leader of an archaeological expedition. Was she incompetent in that leadership position as well, or is being a starship captain "different" for some reason?[[note]]Probably. Would you take someone from an obscure archaeological dig and hand them the keys to a battleship? (Picard doesn't count because he's had extensive training in both fields.)[[/note]]
* PronounTrouble: When Lester-in-Kirk and Coleman are talking amongst themselves, they seem to have trouble settling on what pronoun to use in reference to Kirk-in-Lester.
* PsychoExGirlfriend: Kirk usually has amicable exes, but he and Lester had a toxic relationship.
* SanitySlippage:
** Not that Lester was playing with a full deck to begin with, but she becomes increasingly unhinged as the episode goes on, due to Spock and [=McCoy=] foiling her attempts to get rid of Kirk.
** Contrasted by Kirk-in-Lester, who is justifiably anguished by Lester's actions, but nonetheless keeps calm and rational and discreetly tries to get Spock to realize what's going on.
* SarcasmMode: Spock referring to "Kirk" as "Captain" in the most scathing sarcasm a Vulcan can muster.
* {{Superdickery}}: The [[https://www.youtube.com/watch?v=TbfgOXrSQSY original preview trailer]] doesn't make it clear that a body swap has taken place, and instead tries to sell you on, "Why is Kirk's whole crew mutinying against him? And whoa, did he just order them all executed?"
* TemporarySubstitute: For this, the final episode, Uhura takes the day off and is replaced by a Lieutenant Lisa. (Creator/NichelleNichols had a singing engagement that conflicted with the shooting schedule.)
* TyrantTakesTheHelm: Lester takes over Kirk's body and abuses the captain’s power. Things only get worse when “Kirk” tries to execute the real Kirk who’s trapped in Lester’s body, Kirk, Bones, Spock, and Scotty who start suspecting “Kirk”.
* UndyingLoyalty: Sulu and Chekov accept Spock's statement that "Kirk" isn't Kirk after Lester attempts to have her detractors executed, and make up their minds that no matter what she threatens them with, they will ''not'' assist this person impersonating their captain with her plans.
* VillainousBreakdown: Lester gets these whenever someone contests her orders. Even people who "outrank" her.
* WeInterruptThisProgram: Was a RealLife victim of this trope. UsefulNotes/DwightDEisenhower died the day "Turnabout Intruder" was originally supposed to air. It didn't air until two months later and, as you can imagine, died in the ratings (of course, the show was already canceled anyway).
* WouldntHitAGirl: Lester-as-Kirk hitting Kirk-as-Lester to keep him quiet aroused Spock and [=McCoy's=] suspicions.
----