Star Trek (1966–1969)
17 user 6 critic


Capt. Kirk obsessively hunts for a mysterious cloud creature he encountered in his youth.


Ralph Senensky


Gene Roddenberry (created by), Art Wallace

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Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
DeForest Kelley ... Dr. McCoy
Stephen Brooks Stephen Brooks ... Ensign Garrovick
James Doohan ... Scott
Nichelle Nichols ... Uhura
Jerry Ayres Jerry Ayres ... Rizzo
Majel Barrett ... Nurse Chapel
Walter Koenig ... Chekov


Captain Kirk is haunted by a creature from his past when conducting a mining survey on a planet. He first encountered it as a lieutenant aboard the U.S.S. Farragut and blames himself for freezing in a moment of crisis, causing the death of many crewmen. The creature is a cloud-like, gaseous being that lives on the red blood cells found in humans. Obsessed by his desire for revenge and to erase the memory of 11 years ago, he pursues the creature relentlessly, putting in jeopardy an assignment to collect essential medical supplies. Written by garykmcd

Plot Summary | Plot Synopsis


TV-PG | See all certifications »


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Release Date:

15 December 1967 (USA) See more »

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Did You Know?


Second episode in a row in which captain Kirk's capacity of commanding is questioned. See more »


In the first scene, Spock phasers off a sample of rock, which has been clearly pre-cut to fall off on command. See more »


Spock: Do you know what it is, Captain?
Capt. Kirk: [referring to the lethal gaseous entity] Something that can't possibly exist... but it does.
[looks on to dead crewmen sprawled on the ground]
See more »

Alternate Versions

Special Enhanced version Digitally Remastered with new exterior shots and remade opening theme song See more »


Featured in Bring Back... Star Trek (2009) See more »

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User Reviews

I Haven't the Foggiest
29 April 2014 | by HitchcocSee all my reviews

Kirk is carting around baggage from eleven years ago, when he failed to act as a cloud that smelled sweet, like honey, appeared and several were killed. The crew is extracting some incredible ore when Kirk recognizes that smell. Three red shirts are sent to investigate. Two are killed by the cloud and one is badly injured. The Enterprise is supposed to dock with the Yorktown to bring important medical supplies. All Kirk can think of is the power of that cloud which has reintroduced his biggest failure. The cloud sucks the red corpuscles out of the bodies of its victims. A young ensign, son of an old friend of Kirk's is enlisted, and fails, just as Kirk did, to kill the foggy entity. The thing travels through space and the issue becomes what can be done to stop it. Simple phaser fire doesn't work. Kirk now becomes psychologist and pursuer as he allies himself with the young man. It works pretty well.

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