TOS S01E15: "Balance Of Terror"

"In this galaxy, there's a mathematical probability of three million Earth-type planets.  And in all the Universe, three million, million galaxies like this.  And in all of that, and perhaps more, only one of each of us.  Don't destroy the one named 'Kirk'." - Dr. McCoy

Well, we've rather quickly arrived at my favorite TOS episode:  "Balance Of Terror".  It's got it all...

• Great Star Trek history:  Not only is it the introduction of the Romulans (my favorite Trek aliens), but it's also the introduction of the Earth-Romulan War (my favorite part of Trek history that we never got to see done properly on-screen grumble grumble grumble).  Along with this come many of the established bits of Trek canon that sometimes provide fodder for nerd debates--When did Romulans acquire warp technology?  How much was known of the relationship between Vulcans and Romulans, and when was it known?
• Starship combat!  In what mimics a confrontation between a surface ship and a submarine, USS Enterprise is pitted against a Romulan Bird-of-Prey, which is equipped with another piece of Treknology that we're seeing for the first time--the cloaking device. 
• Kirk almost gets to perform a wedding!  I'm kidding.  That part is stupid.  And what, no one puts on their dress uniform for a quickie starship wedding?  Not even Kirk's wicked awesome avocado number?
  
  
  
• The remastered version of this episode rules, mainly because of the more-detailed CGI used for the BoP.
• Also, Mark Lenard (who we later come to know and love as Sarek) is amazeballs in this episode.
• The Romulan commander toooooootally talks about pulling a Crazy Ivan.  But Kirk's too smart for him.
• We see some interesting things in USS Enterprise's weaponry, which--to my memory--are all unique to TOS:  Her phasers are controlled by a "phaser crew" from a separate location on the ship from the bridge, although some control seems to still be possible from the bridge (and in later series/films, tactical control is exercised entirely from the bridge).  And the phasers are shown to be able to fire a fixed distance and "detonate" in a burst-like pattern.  My memory is a little fuzzy on exactly when photon torpedoes make their appearance in TOS, but my guess is that once those weapons were introduced the phaser no longer needed to have this functionality.
• Ha!  We also get the "jettison debris out the torpedo tube" trick.  This is a straight-up submarine movie in space.  The "sub battle in space" motif will be used again for the starship combat portions of The Wrath Of Khan, although in that movie it's more like two submarine stalking one another (USS Enterprise and USS Reliant in the Mutara Nebula).
• There's an incredible scene in this episode between Kirk and McCoy where Kirk bears his soul about the burdens of command, and McCoy responds with the quote at the top of this entry.  Pretty touching dialog for a 1960s pulp sci-fi series.
• This is the second episode where we see Uhura take over the navigation station.

I love this episode for all of the reasons above and below.  There are two kinds of Trek that I really, really enjoy:  honest-to-goodness sci-fi stories, and thrilling allegory for struggles in our own time.  "Balance Of Terror" is the later, with the commander of each vessel struggling over the decisions they have to make that could lead to war.  The episode also touches upon prejudices from conflicts long past.  And yeah, I make fun of the wedding...but that's mainly because the scene itself at the beginning is goofy.  It's actually a wonderful way of framing the rest of the episode.  While those commanders are struggling with their decisions, and the men and women in service of their governments struggle with their prejudices and duty, we see on either end of that a couple in love, impacted by the conflict.  It's a pretty classic way to tell a "war" story, and it works well in this episode.

And "Balance Of Terror" does all of this while also delivering some quality suspense and action.

Those same qualities are what I find myself responding to time and again in some of the best of Trek.  They're some of the reasons why DS9 remains my favorite series, and they're the reasons "Balance Of Terror" is my favorite TOS episode.