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One of Our Planets Is Missing 

The crew of the Enterprise must stop a living planet-consuming cloud before it attacks an inhabited world.


Hal Sutherland


Gene Roddenberry (created by), Marc Daniels | 1 more credit »




Episode complete credited cast:
William Shatner ... Capt. Kirk (voice)
Leonard Nimoy ... Mr. Spock (voice)
DeForest Kelley ... Dr. McCoy (voice)
George Takei ... Sulu (voice)
Nichelle Nichols ... Uhura (voice)
Majel Barrett ... Cosmic Cloud (voice)
James Doohan ... Scott / Commodore Robert Wesley / Lt. Arex (voice)


A huge cosmic cloud moves into the outer fringe of the galaxy, so Starfleet Command sends the Enterprise to investigate. Sensors show it as a strange combination of matter and energy that engulfs and feeds on the energy of planets. Its deliberate course change towards the populated planet of Mantilles indicates it could be intelligent. Kirk sees it as a threat to every planet in the galaxy and, if they can't communicate with it and make it stop, he will have destroy it.

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TV-PG | See all certifications »

Did You Know?


Some of the shots of Earth, shown to Spock on a computer screen as he is melding with the cloud intelligence, were taken from stock footage of Lassie's Rescue Rangers (1973), a Filmation TV show simultaneous in production. The scenes that came from the Lassie show feature children running with a dog. See more »


When Commodore Wesley appears on the computer monitor in Kirk's quarters, Wesley's shoulder is visible on another, separate view screen right next to him. See more »


Mr. Spock: It would be best if you return to your origin, the way you came. Will you do this?
Cosmic Cloud: A long journey.
Mr. Spock: Will you return?
See more »

User Reviews

Rather familiar but with a totally silly ending.
9 April 2015 | by MartinHaferSee all my reviews

This episode of the animated "Star Trek" is very reminiscent of several other Trek episodes--particularly "The Doomsday Machine" and especially "The Immunity Syndrome". Because of its familiarity, Trekkies will probably like it since it seems much more like a real Trek show than the previous episodes. On the other hand, it's not exactly original and the ending is pretty stupid.

There's a planet-eating cloud in space. It's going to eat Mantilles and kill millions unless the Enterprise can stop it. But there is a problem--the Prime Directive doesn't want Federation craft killing other life--and the cloud is alive! So what will they do? Yup-- call on Spock to do a mild meld with this thingie and ask it to leave, of course! You just have to see this part of the show--it's unintentionally funny.

I gave this one a 5 because like all these cartoons, the animation totally sucks and the story idea not exactly original.

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Release Date:

22 September 1973 (USA) See more »

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Technical Specs



Color | Color (technicolor)
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