Yesteryear

TAS: Season 1 Episode 2
Air Date: September 15th, 1973

Plot

The Enterprise returns to the Guardian of Forever and use the time portal to learn about history. But when Kirk and Spock return from Orion's early history, no-one aboard the Enterprise knows who Spock is. We learn that Spock had died as a young boy, killed during a test known as Kahs-wan. During the test, he was attacked by an animal and saved by a cousin. Thinking back on the situation the cousin looked like Spock. The conclusion was that since Spock was in Orion's history when others were visiting Vulcan history, it must have removed the second Spock from saving himself.

Spock uses the Guardian to go back to Vulcan 30 years ago where he meets his father and pretends to be Sarek's cousin. He witnesses himself being bullied for being half human. Spock finds out that he is a month early for the Kahs-wan but that it wasn't at the Kahs-wan that he was attacked but that night he had tried to do the Kahs-wan by himself to make sure he can do it. Older Spock follows young Spock and his pet Sahlet IChaya and saves him from a beast.

Young Spock realizes that I Chaya was poisoned during the fight and young Spock asks older Spock to stay beside I Chaya while he gets a healer. The healer arrives but it was too late. Older Spock teaches Young Spock that a Vulcan doesn't cry and that he should honour his pet for his bravery and everything he did before. Young Spock decides to put down I Chaya rather then letting him suffer.

Commentary

In this episode they show Spock's pet, I Chaya which Spock referenced in the Episode of Journey to Babel where he said "On Vulcan the teddy bears are alive, and they have 6-inch fangs" 

Quotes

"By understanding every life comes to an end when time demands it. Loss of life is to be mourned, but only if the life was wasted." - Older Spock

"I've got my medical scanners all set up for a Vulcan. I have to recalibrate every time I run a physical on you, Spock." - McCoy

"Doctor McCoy, you do not know your good fortune. IF the times were different, you would have to recalibrate for an Andorian." - Spock

"If that was supposed to be a joke, Spock, I have to remind you Vulcans don't tell jokes." - McCoy

"Times change, Doctor. Times change." - Spock