Star Trek (1966–1969)
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The Enemy Within 

A transporter malfunction splits Captain Kirk into two halves: one meek and indecisive, the other violent and ill tempered. The remaining crew members stranded on the planet cannot be beamed up to the ship until a the problem is fixed.



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Episode complete credited cast:
Ed Madden ...
Fisher (as Edward Madden)
Garland Thompson ...
Jim Goodwin ...


While beaming back aboard the Enterprise, a transporter malfunction results in two vastly different Captain Kirks being beamed aboard. His personality has in effect been split into two. One Captain Kirk is weak and indecisive, fearful of making any kind of decision; the other is a mean-spirited and violent man who likes to swill brandy and force himself on female crew members. Meanwhile, as Scotty struggles to repair the transporter, the landing party is stuck on the planet below with temperatures falling rapidly. Written by garykmcd

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Release Date:

6 October 1966 (USA)  »

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Aspect Ratio:

1.33 : 1
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Did You Know?


There are two split screens used: after Kirk's double is neck-pinched and, in sickbay, when he takes the hand of his counterpart. All other instances of the two Kirks appearing in the same shot were done using doubles. See more »


Spock erroneously refers to himself as "second officer". His title is "first officer" or "second-in-command". See more »


Sulu: We're using hand phasers to heat the rocks. One phaser quit on us, three still operating. Any possibility of getting us back aboard before the skiing season opens down here?
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Referenced in Family Guy: The Hand That Rocks the Wheelchair (2011) See more »


Theme From Star Trek
Written by Alexander Courage
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User Reviews

The Most Brutal, Thoughtless Captain Kirk
22 June 2006 | by (United States) – See all my reviews

The title itself is misleading in this episode and so are the first few scenes. The second Kirk who materializes on the transporter platform after a strange malfunction is not a duplicate of the real Capt. Kirk, nor is he, as it turns out, an enemy to Kirk's existence. Kirk himself gets it wrong as he describes what happened in his log. Neither of the Kirks after the credits is the real one in this episode. They are both half of the real Kirk, who no longer exists at this point. The meek, mild half is more difficult to notice as not being quite real while his confidence slips away more gradually. The violent, animalistic half gives himself away more easily as he demands Saurian brandy from Dr. McCoy and then tries to rape Yeoman Rand. Yes, the crew who encounter him still believe it's Capt. Kirk, but it's as if he's taken some bad drugs lately - not very captainly behavior.

Shatner gets to tap into his inner rage with his performance as the so-called evil Kirk version in this episode. This version of Kirk is always sweating, eyes furtive, and then usually spasming into a screaming fit as if totally out of control or seriously ill. It's a startling transition whenever we switch from the calm, tired Kirk (also ill, tho in a benign fashion) to this obvious madman (the lighting in these scenes also helps). However, by the 3rd act, we learn, via Spocks's analytical observations, that all of Kirk's power of command rests in this evil half. Of course, the entire episode debunks the whole simplistic concept of good and evil; the supposed negative side of Kirk is needed for him to function as captain. We humans are made up of many parts, this story says, and all of these are necessary, whether labeled positive or negative (one can say the same for business and political leaders).

This episode has some pretty intense moments, especially the scene of the negative Kirk attacking Rand - it's a bit too real and is uncomfortable to watch, a disturbing depiction of attempted rape. I'm not sure what to make of Spock's snide remark to her at the end - maybe his intent was to diffuse the whole thing, but it seemed quite inappropriate - though she just took it in stride. The glaring flaw in the episode, in retrospect, is that no shuttlecrafts were sent to rescue the men trapped on the planet below from freezing to death. Maybe the crafts were all in disrepair or there was something in the atmosphere (or maybe they weren't written into the show, yet). Of course, this added dilemma of crew members slowly dying served to underscore the positive Kirk's growing indecision on such matters. It was probably in this episode that we first learned how infallible a starship captain must be, even if just for the sake of appearance.

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