Star Trek: The Animated Series (1973): S01E02 – Yesteryear


“Yesteryear” is the second episode of the first season of the animated American science fiction television series Star Trek.

It first aired in the NBC Saturday morning lineup on 15 September 1973, and was written by veteran Star Trek writer D.C. Fontana.

Widely regarded as one of the best episodes of the series, it was nominated for a Daytime Emmy Award. “Yesteryear” guest-starred Mark Lenard in the role of Spock’s father, Sarek.

In this episode, Enterprise First Officer Spock must travel in time to his childhood and keep his younger self from dying and being replaced by an Andorian on his ship.


On stardate 5373.4, Captain Kirk and Spock return from a time-travelling research project they have been conducting with the use of the Guardian of Forever and Starfleet historians. When they emerge from the portal, they discover that no one on board the Federation starship Enterprise recognises Spock. Kirk and Spock are further surprised to see that an Andorian officer, Commander Thelin, has replaced Spock as first officer.

In the new timeline, history has recorded that Spock died at age seven undergoing the Kahs-wan ordeal on Vulcan. However, Spock remembers that when he took the Kahs-wan, his life was saved by Selek – an adult relative – when a desert creature with poisonous claws called a le-matya had attacked them. While Kirk and Spock were in the portal, the Guardian and historians had run a scan of recent Vulcan history. The pair quickly realise that as they were observing the birth of Orion at the time, Spock could not have been in two places at once to save himself as a child. Spock must go back through the time gate to his childhood, and save the life of the child he was. For his part, Thelin is supportive of Spock’s efforts despite its consequences on his own existence and the officers respectfully wish each other long and prosperous lives in whatever circumstances the hopefully repaired timeline would put them in.

At first, this proceeds smoothly: Spock assumes the identity of Selek, a distant cousin of Sarek, and is welcomed into the home of Sarek and Amanda Grayson. “Selek” journeys into the desert to find his younger self, and saves the boy. However, I Chaya – Spock’s pet sehlat – has been gravely wounded and “Selek” sends the younger Spock back to fetch a Healer. Spock returns with the Healer who tends to I Chaya and informs Selek and Spock that there is nothing he can do. Young Spock is offered a choice: either I Chaya can be treated with medicines (but will still die slowly in obvious pain) or his pet can be allowed to die quickly with dignity. Young Spock chooses the latter, and I Chaya dies peacefully. By making this choice, Spock has thus chosen the Vulcan way of life – logic and emotional control – and his elder self, successful in repairing history, returns to the restored present day, but not before teaching his younger self how to perform the Vulcan nerve pinch.

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Production & Filming Details

  • Director(s): Hal Sutherland.
  • Writer(s): DC Fontana.
  • Release Date: 15 September 1973.
  • Running Time: 30 minutes.
  • Country: US.
  • Language: English.

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