All Our Yesterdays (Star Trek: The Original Series)

The Federation starship Enterprise arrives at the planet Sarpeidon, whose star is soon to go nova. Surprised to find the surface devoid of humanoid life, Kirk, Dr. McCoy and Spock beam down to investigate. They encounter one last remaining resident, a librarian named Mr. Atoz who scolds them for being very late. Aware of the imminent destruction, Mr. Atoz tells the perplexed landing party that he will soon escape to rejoin his own family. Mr. Atoz shows them the Atavachron, a machine with a time portal that connects to Sarpeidon's past. Suddenly, they hear a woman scream. Kirk instinctively runs through the portal and McCoy and Spock follow. Mr. Atoz tries to warn them all that they were not "prepared".

Kirk finds himself alone and in the midst of a duel in a period similar to England in Earth's 17th century while McCoy and Spock travel back 5,000 years to Sarpeidon's ice age. They cannot locate the portal's entrance to return but the three are able to speak to each other. Spock correctly surmises that the Sarpeidons have all escaped to their planet's past.

As McCoy and Spock search for shelter from a severe blizzard, Kirk tries to bring the woman who screamed back through the portal but is unable to find it. The woman is a thief, and the policemen who soon come to arrest her also arrest Kirk. They hear Kirk speaking to his friends and suspect him of being a witch. In the jail, Kirk mentions the Atavachron to the interrogating prosecutor. This visibly startles him, and Kirk suspects he is also from the future. As Kirk later attempts an escape, the prosecutor returns and confirms Kirk's suspicions but explains that returning to the future would be fatal. Kirk mentions Atoz's warning that they had not been "prepared" before going through the portal. At that, the prosecutor insists that Kirk must return, because an "unprepared" person cannot survive in the past for more than a few hours. The prosecutor quickly leads Kirk to the portal, and Kirk returns to the present.

McCoy and Spock are saved by Zarabeth (Mariette Hartley), a beautiful woman who takes them to a sheltering cave. As McCoy recovers from severe exposure, Zarabeth explains to Spock that she too is from Sarpeidon's future, but a tyrant banished her to this era. She also explains that the Atavachron is a one-way trip. Spock uncharacteristically accepts this and becomes increasingly hostile to McCoy's continued desire to return to the present. Spock also begins to fall in love with Zarabeth, and physically attacks McCoy when he accuses Zarabeth of not telling the full truth. McCoy realizes that Spock is reverting to the barbarism of the ancient Vulcans, and this shocks Spock into controlling his emotions.

Back in the library, Kirk attempts to enlist Mr. Atoz in the search for his friends. Despite Kirk's explaining that they are not from this planet, Atoz stuns him and tries to force him back into the portal. Kirk awakens just in time, overpowers Atoz and forces him to help find McCoy and Spock. Eventually Kirk is able to talk with the two, and with the portal reopened, Spock and Zarabeth bid a tearful farewell. Upon their return, Atoz places his own data disc in the Atavachron and hurries through the portal to his chosen era. Back in the present, Spock quickly reverts to his normal self, and with little time to spare they are beamed back to the Enterprise.

In 2015, SyFy ranked this episode as one of the top ten essential Star Trek original series episodes.[1]

In 2016, The Hollywood Reporter rated "All Our Yesterdays" the 39th best episode of all Star Trek episodes.[2]

In 2016, SyFy ranked "All Our Yesterdays" as the 12th best time-travel plot of all episodes of the Star Trek franchise.[3] They point out the episode offered fresh perspective on time travel by exploring the past of an alien world, as well as an interesting exploration of the characters Kirk, Spock, and McCoy.[4]

A 2018 Star Trek binge-watching guide by Den of Geek, recommended this episode for featuring the trio of characters Kirk, Spock, and Bones of the original series.[5]

In 2019, Nerdist included this episode on their "Best of Spock" binge-watching guide.[6] They also ranked it the tenth best time travel episode of the Star Trek franchise, including the later 750+ episodes.[7] They note this episode for featuring Spock's travels to an ancient ice age of an alien world, and at that time his emotions are triggered by a woman and the effects of time travel.[7] In the series, they remarked that normally the character does not have much emotion, so seeing the character deal with emotions provides a change of pace for the character's presentation.[7]

Author Ann C. Crispin wrote two non-canon novel sequels to this episode, titled Yesterday's Son, and Time for Yesterday.

Wikiquote has quotations related to: "All Our Yesterdays"

• "All Our Yesterdays" at StarTrek.com
• "All Our Yesterdays" on IMDb

• "All Our Yesterdays" at Memory Alpha (a Star Trek wiki)
• "All Our Yesterdays" at TV.com
• "All Our Yesterdays" Remastered version at TrekMovie.com
• "All Our Yesterdays" December 12, 1968, draft; report & analysis by Eric Paddon
• "A Handful of Dust" precursor to "All Our Yesterdays"; story outline and analysis by Dave Eversone