Star Trek: Season 1, Episode 5

The Enemy Within (6 Oct. 1966)

TV Episode  -   -  Action | Adventure | Sci-Fi
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Ratings: 7.8/10 from 1,268 users  
Reviews: 14 user | 10 critic

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

Plot Summary | Plot Synopsis


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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?


Unable to beam up Lieutenant Sulu in this episode, the transporter was a plot device intended to eliminate the pacing and production problems involved in depicting the ship landing and taking off all the time. Budgetary constraints on effects were also a consideration. The first landing of a starship would not occur until Star Trek: Voyager: The 37's (1995), broadcast 28 August 1995. See more »


While the Enterprise does house a fleet of shuttlecraft, this feature of the ship had not yet been introduced in the series, thus the reason they are not suggested to retrieve Sulu's endangered away-team. See more »


Sulu: I think we ought to give room service another call. That coffee's taking too long.
See more »


Referenced in Mind Meld: Secrets Behind the Voyage of a Lifetime (2001) See more »

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User Reviews

Dr. Jekyll and Captain Kirk
24 April 2014 | by (United States) – See all my reviews

Kirk is divided in half. He, like the Stevenson Jekyll/Hyde character becomes two people. One exhibiting an animalistic being and the other an outer space Casper Milquetoast. The problem is that the two look exactly. It allows William Shatner to bring out his ultimate ham. He mugs and sneers as the evil side while he whimpers indecisively as the other half. The key is to not destroy everything while the lecherous Kirk is chasing Yeoman Rand, trying to assault her sexually. This becomes an uncomfortable series of events. In some ways, it is quite laughable; on the other hand, it is deadly serious. Spock and the others are in a quandary because they must figure out what is going on. Kirk comes and goes and they are suspicious, but they have no reason to suspect anything other than the fact that he is an incredible mess. Science to the rescue.

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