Star Trek (1966–1969)
35 user 8 critic

Balance of Terror 

The Enterprise must decide on its response when a Romulan ship makes a destructively hostile armed probe of Federation territory.


Vincent McEveety


Paul Schneider, Gene Roddenberry (created by)

Watch Now

With Prime Video





Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
Mark Lenard ... Romulan Commander
Paul Comi ... Stiles
Lawrence Montaigne ... Decius
DeForest Kelley ... Dr. McCoy
Grace Lee Whitney ... Yeoman Rand
George Takei ... Sulu
James Doohan ... Scott
Nichelle Nichols ... Uhura
Stephen Mines ... Tomlinson
Barbara Baldavin Barbara Baldavin ... Angela
Garry Walberg ... Hansen
John Warburton ... The Centurion


The Enterprise answers a distress call from Federation Outpost #4, a monitoring station on the Federation side of the neutral zone with the Romulan Empire. The outposts were established over a century ago and no one has actually seen a Romulan. The Romulan vessel seems to have some type of high energy explosive device as well as a cloaking device to make the ship invisible. When it appears that Romulans bear a strong resemblance to Vulcans, Kirk must deal with a rebellious crew member. He must also engage in a dangerous cat and mouse game with a very intelligent Romulan commander. Written by garykmcd

Plot Summary | Plot Synopsis


TV-PG | See all certifications »






Release Date:

15 December 1966 (USA) See more »

Company Credits

Show more on IMDbPro »

Technical Specs


Sound Mix:




Aspect Ratio:

See full technical specs »

Did You Know?


The Romulan Empire is noticeably modelled after the Roman Empire. The terms Centurion and Praetor are borrowed from Ancient Rome. The only named Romulan in this story introduced himself as Decius, which is a Latin name used in Ancient Rome. Despite the heavy Roman theme, he is the only Romulan character throughout the entire run of the original franchise (1966-2002) to have a Latin or Roman name. This would not happen again until Star Trek (2009) with the Romulan character Nero. See more »


Phasers emit two straight beams. But when Kirk orders phasers to fired, three missiles are launched and explode, which indicates they are photon torpedoes. See more »


Stiles: We enter the Neutral Zone in one minute, Captain.
Dr. McCoy: Do we violate the treaty, Captain?
Mr. Spock: They did, Doctor.
Dr. McCoy: Once inside, they can claim we did. A set-up. They want war, we furnish the provocation.
See more »

Alternate Versions

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


References Run Silent Run Deep (1958) See more »


Theme From Star Trek
Written by Alexander Courage
See more »

Frequently Asked Questions

This FAQ is empty. Add the first question.

User Reviews

"The Enemy Below"
2 June 2009 | by BlueghostSee all my reviews

Nearly ten years before Desilu Studios chanced Star Trek, Robert Mitchum and Curt Jurgens were up on the big screen showing the progenitor to one of Star Trek's more famous episodes in the form of a US Navy DDE (destroyer escort) matching wits with a German U-boat in the South Atlantic. This observation was not my own, but made by a good friend who works for another man that publishes a game based on the classic Star Trek franchise.

Classic Roman society is used as a template for Vulcan cousins, and are assigned a nationalistic and expansionist philosophy, again not unlike Nazi Germany post the Imperial regime from which the Kaiser abdicated power after the first world war.

The episode brings a flavor of the classic U-Boat sub hunt to the science fiction audience, and, remarkably, uses a then recently declassified (and still experimental) technology developed by the USAF; the cloaking device. The idea was to mask bombers (notably the B-51 Hustler if I recall correctly... which I may not) as they drove deep into enemy territory to deliver their payload. It was an airborne mimicry of the submarine concept. It's technical details are too lengthy and esoteric to place in this post (that, and I don't recall all of them now :-)), but the concept, down to its actual name, was used in this episode. And, if memory serves, in Lucas's "The Empire Strikes Back" in a throw away line just after the asteroid chase sequence.

The episode, like the movie upon which it borrows, is rife with tension. One mind is pitted against another in a struggle for life and death. Each is duty bound to vanquish the other. They must act upon their orders to ensure their sides victory. Unlike the feature film, Trek's "Balance of Terror" has a definitive victor. I'll let you guess who it is ;-) But there's more than just a simple WW2 tale put into space operating here. Note the title. Note the period in which this episode and show were made; the Cold War. Marry the two, and keep in mind the various proxy wars both US and USSR waged across the globe, and you'll start to see the larger theme.

Yet, with all this high mindedness, with all the military tactical tension, there are personal costs on both sides. It's not the primary focus of both film and episode, but a reminder of the cost of such conflict among fellow living creatures.

Definitely worth seeing again.


9 of 14 people found this review helpful.  Was this review helpful to you? | Report this
Review this title | See all 35 user reviews »

Contribute to This Page

Olivia Colman of 'The Favourite': "No Small Parts"

Olivia Colman has been nominated for an Academy Award for her performance in The Favourite. We take a look at her evolution from a comedic actress to dramatic performer.

Watch now

Recently Viewed