A powerful artificially intelligent Earth probe, with a murderously twisted imperative, comes aboard the Enterprise and confuses Capt. Kirk as his creator.



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Episode complete credited cast:
Makee K. Blaisdell ...
Singh (as Blaisdel Makee)
Barbara Gates ...
Meade Martin ...
Arnold Lessing ...
Security Guard
Vic Perrin ...
Nomad's Voice (voice)


The Enterprise encounters a powerful energy force that has apparently killed all human life in a solar system with over one billion inhabitants. They identify the culprit as a small space probe that had its origins on Earth. Called Nomad, it merged with another and, as a result, took on a new mission to destroy all biological beings as being imperfect. It believes Captain Kirk to be its creator and, as such, has spared the Enterprise and its crew, at least temporarily. Written by garykmcd

Plot Summary | Plot Synopsis


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Release Date:

29 September 1967 (USA)  »

Company Credits

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Technical Specs


Sound Mix:


Aspect Ratio:

1.33 : 1
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Did You Know?


The alien probe that Nomad collided with was called Tan Ru. See more »


During Nomad's initial attack on the Enterprise, the bridge crew react to the "hit" so violently that the helm/navigation console is lifted clear off the ground and almost tipped over. See more »


Capt. Kirk: [of Nomad's demise] It's not easy to lose a bright and promising son.
Spock: Sir?
Capt. Kirk: Well, it thought I was its mother, didn't it? D'you think I am completely without feelings, Mr. Spock? You saw what it did to Scotty. What a doctor it would have made.
[a beat]
Capt. Kirk: My son, the doctor.
Capt. Kirk: [fists his own heart] Kind of gets you right there, doesn't it?
See more »


Referenced in Team Knight Rider: Apocalypse Maybe (1998) See more »

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User Reviews

2 June 2009 | by (The San Francisco Bay Area) – See all my reviews

Classic Trek aficionados often pan the Third Season of Classic Trek as being the worst of the worst, and specifically they assign "Spock's Brain" as being the absolute worst Star Trek episode ever.

I disagree. I label "The Changeling" as the worst, and not because it was used as the basis for the first Star Trek feature film back in the late 70s.


I just can't stand the execution of this story. The story concept is intriguing enough, but the interpersonal interaction with the mechanical antagonist and Enterprise crew, to me at least, is nearly laughable. If I'm watching classic Trek, and this thing happens to be on the DVD set I've got in the player, then I may keep it on in the background, but it's really painful to watch at times.

To me this episode is the poster boy for people to point at who think Star Trek is stupid. And you know what? I'd be hard pressed to deny them that claim after watching this particular installment.

I just don't know what went wrong here. For all the money that they had to spend on this episode, was this really the best the creative team could come up with? One is reminded of "Red Dwarf's" props department, and the Holly-Hop drive prop. Yeah, it's that bad.

Shatner and gang give us Kirk and crew to outwit a schizophrenic robot. It's a little cliché in that regard, which just adds another nail in the coffin for this episode, but it's not really the defining moment as some may think.

Not a worthy installment of the franchise, if somewhat interesting. Good acting (save for M-5), poor production values (again, M-5), and a lack of vision on how to properly present the story.

Take it for what it's worth.

4 of 29 people found this review helpful.  Was this review helpful to you?

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