Star Trek (1966–1969)
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The Immunity Syndrome 

The Enterprise encounters a gigantic energy draining space organism that threatens the galaxy.



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Episode complete credited cast:
John Winston ...
Lt. Kyle


The Enterprise is sent to investigate the disruption of the Gamma VII-A solar system and the destruction of the U.S.S. Intrepid, staffed solely by Vulcans. When they arrive they find a large dark mass floating in space that is draining energy from everything around it, including the Enterprise. Drawn into the mass, they find a huge amoeba-like creature and Kirk must decide which of his two friends, McCoy or Spock, to send into it aboard a shuttle craft on a mission of no return. Written by garykmcd

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TV-PG | See all certifications »


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Release Date:

19 January 1968 (USA)  »

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Did You Know?


The young crew woman whom Kirk admires as he records his log at the end of this show appears to be the same extra who portrayed the other female Klingon seen in "Day of the Dove". See more »


At one point during Kirk, Spock, and McCoy's discussion of using a shuttle craft to determine how to destroy the organism, McCoy crosses over so that he is next to Spock, but the cuts between them show the same exact background, even though they are facing each other (This was done this way because there was no wall on the set behind McCoy, from Spock's point of view). See more »


Christine Chapel: Doctor, they seem to be stabilizing.
Dr. McCoy: But at a dangerously low level. Well, we're still alive. I suppose that's something.
See more »


Referenced in Star Wars: Episode IV - A New Hope (1977) See more »

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User Reviews

Well-written, visually-striking, mind-blowing.
29 November 2008 | by See all my reviews

One of the best and most memorable episodes of the original Trek series.

First off, the "star" of the show: the gigantic space-amoeba critter was such an impressive sight in the original series, that when it was re-released in the recent "enhanced" episodes with remastered HD format and state-of-the-art effects, the creature itself was left virtually unchanged. In fact, IMO, the critter looked better unenhanced.

This is doubly impressive in light of the show's budget limitations, being a relatively inexpensive process put to very good effect.

On top of that, the writing doesn't fall into the bogus-science 'treknology' gibberish and continuity problems that plagued and dragged so many episodes into mediocrity. The science in this episode is rock-solid, one of the few Trek episodes that qualifies as true hard-core science fiction.

The story itself is slowish for Star Trek, more brooding than action, but it works without insulting your intelligence in the process.

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