History Recap / StarTrekS3E23AllOurYesterdays

* NubileSavage: Spock and Bones meet one of these. It turns out she's from the planet's future, and was exiled to the distant past via a time machine by a dictator.
* OffscreenTeleportation: In the teaser, the dramatic moment leading into the opening credits is Mr. Atoz apparently doing this, always turning up ahead of the away team as it moves around the library. It's subsequently explained that he has a couple of duplicates of himself, created by some unexplained process, that help him run the library.

Notably also the last episode of the series if you put them in chronological order by Stardate. It's generally considered one of the highlights of the often-shaky third season, and a much better series finale than [[Recap/StarTrekS3E24TurnaboutIntruder "Turnabout Intruder"]].

* OOCIsSeriousBusiness: Spock starts out getting visibly frustrated, escalating into murderous rage. He kisses a girl passionately. [[ArsonMurderAndJaywalking And he eats meat.]] It seems that all Vulcans have a loose psychic link with one another[[note]]Continuity! In "The Immunity Syndrome" this is how Spock senses the destruction of the ''Intrepid'', though he doesn't pick up details. In a line in "Amok Time" that got cut for time, he says Vulcans always know their proximity to their homeworld.[[/note]], and since they are thousands of years in the past and all Vulcans are in a savage state....,

** For Zarabeth and the judge, at least, it is entirely true.

* BadassGrandpa: The librarian manages to fight off Captain Kirk quite handily.

* SwordFight: Kirk gets in one with a Musketeer. He wins! He can sword fight with Musketeers, he can hold his own against [[Recap/StarTrekS1E18Arena the Gorn]], but he can't take on [[BadassGrandpa an 80 year old librarian?]]

** She also seems familiar with the "canting" speech used by Creator/MarkTwain in ''Literature/ThePrinceAndThePauper''. Twain may have used the 16th-century book ''Musa Pedestris'' as a source (he has the gang of thieves singing a song from it).

* ArtisticLicensePhysics: Generally speaking, the only stars that can cause supernovae are white dwarfs and red giants, neither of which would be able to support an Earth-like environment on any orbiting planet. The idea that Sarpeidon would have been remotely habitable mere hours before their sun erupted is just about impossible.

!!Tropes for this episode include:

Notably also the last episode of the series if you put them in chronological order by Stardate. It's generally considered a much better series finale than [[Recap/StarTrekS3E24TurnaboutIntruder "Turnabout Intruder"]].

* SamusIsAGirl: The [[StarWars Jawa]] with gigantism that saves Spock and Bones from freezing to death pulls back the hood to reveal a young Mariette Hartley!

* DissonantSerenity: Spock does not mourn having to leave Zarabeth permanently even after experiencing positive emotions all thanks to her for at least a few hours. Spock defends his underreaction that Zarabeth died tens of thousands of years before the time he is in currently, when taking into account the time travel door it just happened seconds ago.

* LiteraryAllusionTitle: From Shakespeare's ''Theatre/{{Macbeth}}'': "And all our yesterdays have lighted fools the way of dusty death...."

** The Atavachron, a portal which allows the planet's people to go back in time to live with, essentially, their ancestors (i.e., [[https://en.wikipedia.org/wiki/Atavism atavism]]). Lampshaded by Spock, though he doesn't define the "intriguing nomenclature".

* MeaningfulName: What better name for a librarian than "A to Z"?

* OutOfCharacterMoment: The original script Spock falling in love and kissing Zarabeth but averted in the filmed episode at Creator/LeonardNimoy's insistence. Instead, his behavior was {{hand wave}}d with the explanation that, having gone back in time, he became like the savage Vulcans of that time.

Notably also the last episode of the series if you put the Stardates in chronological order. It's generally considered a much better series finale than [[Recap/StarTrekS3E24TurnaboutIntruder "Turnabout Intruder"]].

* BadassGrandpa: The librarian manages to fight off captain Kirk quite handily.

[[caption-width-right:350:Spock and Zarabeth.]]

* OOCIsSeriousBusiness: Spock starts out getting visibly frustrated, escalating into murderous rage. He kisses a girl passionately. [[ArsonMurderAndJaywalking And he eats meat.]] It seems that all Vulcans have a loose psychic link with one another[[note]]Continuity! In "The Immunity Syndrome" this is how Spock senses the destruction of the ''Intrepid'', though he doesn't pick up details. In a line in "Amok Time" that got cut for time, he says Vulcans always know their proximity to their homeworld.[[/note]], and since they are thousands of years in the past and all Vulcans are in a savage state....

* [[UngratefulBastard Ungrateful Bitch]]: The redhead that Kirk saves from a Musketeer (seems he was going to arrest her for pickpocketing) is quick to order a burnt stake for him.

* OhCrap: Bones realizes Spock isn't putting up with his shit.

* TemporalSickness: The inhabitants of the planet are sent back to their past to escape their star going nova. Kirk, Spock and Bones travel without being given the treatment, and will die unless they can [[IncrediblyLamePun get back in time.]]