Star Trek (1966–1969)
19 user 6 critic

The Immunity Syndrome 

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


Joseph Pevney


Gene Roddenberry (created by), Robert Sabaroff

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Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
DeForest Kelley ... Dr. McCoy
James Doohan ... Scott
Nichelle Nichols ... Uhura
Walter Koenig ... Chekov
John Winston John Winston ... Lt. Kyle
Majel Barrett ... Christine Chapel


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

Plot Summary | Plot Synopsis


TV-PG | See all certifications »


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Release Date:

19 January 1968 (USA) See more »

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Technical Specs


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Did You Know?


This is the last episode directed by Joseph Pevney who, along with Marc Daniels, holds the record for directing the most number of episodes for the series. See more »


At least twice, Kirk presses a button to make a ship-wide announcement. When done with the announcement, he resumes speaking to the others on the bridge without deactivating his announcement system. See more »


Capt. Kirk: Captain's Log, stardate 4307.1. Approaching Starbase 6 for a much-needed period of rest and recreation. The crew has performed excellently, but is exhausted, and I, too, am looking forward to a nice period of rest on some lovely...
[he watches a pretty yeoman pass his chair]
Capt. Kirk: ... planet.
See more »

Alternate Versions

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


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

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User Reviews

The most basic building block of animal life.
1 February 2014 | by bkoganbingSee all my reviews

One of the most fascinating things I have always found about this particular Star Trek episode is that no one brought in the prime directive when dealing with what they found. In fact it was life in its most basic form after exponentially increasing to the size of a couple of solar systems.

No doubt in the world about what to do with a one cell organism that size. It can't think and reason, all it does is eat and reproduce and we don't want more than one of those roaming around the galaxy.

Leonard Nimoy and DeForest Kelley do take their rivalry to some absurd levels in this episode. Nevertheless the whole Enterprise team pulls together as a team to beat this thing.

How do you deal with an organism? Go back to biology one for the answer.

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