The Star Trek: The Original Series Episodes That Best Define the Franchise

By the time my generation got to watch Star Trek: The Original Series, the episodes often were being presented in top-ten marathons. When I was ten-years-old, for the 25th Anniversary of Star Trek, I tape-recorded a marathon of ten episodes that had all been voted by fans as the best-ever installments of The Original Series. Later, I got lucky and found Trek stickers at the grocery store and was able to label my VHS tapes correctly. But do I think all the episodes that were in that marathon back in 1991 were really the best episodes of all of the classic Star Trek? The short answer: no. Although I love nearly every episode of the first 79 installments of Star Trek, I do think that certain lists have been created by what we think should be on the list rather than what episodes really best represent the classic show. 

This is a long-winded way of saying, no, I didn’t include “Amok Time” or “The Menagerie” on this list because, as great as they are, I don’t think they really represent the greatest hits of the series. Also, if you’ve never watched TOS, I think those two episodes will throw you off cause you’ll assume Spock is always losing his mind or trying to steal the ship. If you’ve never watched TOS, or you feel like rewatching it with fresh eyes, I feel pretty strong that these 10 episodes are not only wonderful, but that they best represent what the entire series is really about. Given this metric, my choice for the best episode of TOS may surprise you…

10. “The Man Trap” 

The first Star Trek ever episode aired should not be the first episode you watch. And yet, you should watch it at some point. The goofy premise concerns an alien with shaggy dog fur, suckers on its hand, and a face like a terrifying deep-sea fish. This alien is also a salt vampire that uses telepathy that effectively also makes it a shapeshifter. It’s all so specifically bonkers that trying to rip-off this trope would be nuts. Written by science fiction legend George Clayton Johnson (one half of Logan’s Run authorship) “The Man Trap” still slaps, and not because Spock (Leonard Nimoy)  tries to slap the alien. Back in the early Season 1 episodes of Star Trek, the “supporting” players like Uhura and Sulu are actually doing stuff in the episode. We all talk about Kirk crying out in pain when the M-113 creature puts those suckers on his face, but the real scene to watch is when Uhura starts speaking Swahili. The casual way Uhura and Sulu are just their lovable selves in this episode is part of why we just can’t quit the classic Star Trek to this day. Plus, the fact that the story is technically centered on Bones gives the episode some gravitas and oomph. You will believe an old country doctor thinks that salt vampire is Nancy! (Spoiler alert: It’s not Nancy.)

9. “Let that Be Your Last Battlefield” 

There are two episodes everyone always likes to bring up when discussing the ways in which Star Trek changed the game for the better in pop culture’s discourse on racism: “Plato’s Stepchildren” and this episode, “Let that Be Your Last Battlefield.” The former episode is famous because Kirk and Uhura kiss, which is sometimes considered the first interracial kiss on an American TV show. (British TV shows had a few of those before Star Trek, though.) But “Plato’s Stepchildren” is not a great episode, and Kirk and Uhura were also manipulated to kiss by telepaths. So, no, I’m not crazy about “Plato’s Stepchildren.” Uhura being forced to kiss a white dude isn’t great.

But “Let that Be Your Last Battlefield,” oddly holds up. Yep. This is the one about space racism where the Riddler from the ‘60s Batman (Frank Gorshin) looks like a black-and-white cookie. Is this episode cheesy? Is it hard to take most of it seriously? Is it weird that Bele (Frank Gorshin) didn’t have a spaceship because the budget was so low at that time? Yes. Is the entire episode dated, and sometimes borderline offensive even though its heart is in the right place? Yes. Does the ending of the episode still work? You bet it does. If you’re going to watch OG Star Trek and skip this episode, you’re kind of missing out on just how charmingly heavy-handed the series could get. “Let that Be Your Last Battlefield” is like a ‘60s after-school special about racism, but they were high while they were writing it.

8. “Arena”

You’re gonna try to list the best episodes of Star Trek: The Original Series and not list the episode where Kirk fights a lizard wearing gold dress-tunic? The most amazing thing about “Arena” is that it’s a Season 1 episode of The Original Series and somehow everyone involved in making TOS had enough restraint not to ever try to use this Gorn costume again. They didn’t throw it away either! This famous rubber lizard was built by Wah Chang and is currently owned by none other than Ben Stiller.

So, here’s the thing about “Arena” that makes it a great episode of Star Trek, or any TV series with a lizard person. Kirk refuses to kill the Gorn even though he could have, and Star Trek refused to put a lizard costume in a bunch of episodes later, even though they totally could have. Gold stars all around.

7. “Balance of Terror”

The fact that Star Trek managed to introduce a race of aliens that looked exactly like Spock, and not confuse its viewership is amazing. On top of that, the fact that this detail isn’t exactly the entire focus of the episode is equally impressive. The notion that the Romulans look like Vulcans is a great twist in The Original Series, and decades upon decades of seeing Romulans has probably dulled the novelty ever so slightly. But, the idea that there was a brutally cold and efficient version of the Vulcans flying around in invisible ships blowing shit up is not only cool, but smart.

“Balance of Terror” made the Romulans the best villains of Star Trek because their villainy felt personal. Most Romulan stories in TNG, DS9, and Picard are pretty damn good and they all start right here.

6. “Space Seed”

Khaaaan!!!! Although The Wrath of Khan is infinitely more famous than the episode from which it came, “Space Seed” is one of the best episodes of The Original Series even if it hadn’t been the progenitor of that famous film. In this episode, the worst human villain the Enterprise can encounter doesn’t come from the present, but instead, the past. Even though “Space Seed” isn’t considered a very thoughtful episode and Khan is a straight-up gaslighter, the larger point here is that Khan’s evilness is connected to the fact that he lived on a version of Earth closer to our own.

The episode’s coda is also amazing and speaks of just how interesting Captain Kirk really is. After Khan beat the shit out of him and tried to suffocate the entire Enterprise crew, Kirk’s like “Yeah, this guy just needs a long camping trip.” 

5. “A Piece of the Action”

A few years back, Saturday Night Live did a Star Trek sketch in which it was revealed that Spock had a relative named “Spocko.” This sketch was tragically unfunny because TOS had already made the “Spocko” joke a million times better in “A Piece of the Action.” When you describe the premise of this episode to someone who has never seen it or even heard of it, it sounds like you’re making it up. Kirk, Spock, and Bones are tasked with cleaning-up a planet full of old-timey mobsters who use phrases like “put the bag on you.” Not only is the episode hilarious, but it also demonstrates the range of what Star Trek can do as an emerging type of pop-art. In “A Piece of the Action,” Star Trek begins asking questions about genres that nobody ever dreamed of before. Such as, “what if we did an old-timey gangster movie, but there’s a spaceship involved?”

4. “Devil in the Dark”

When I was a kid, my sister and I called this episode, “the one with giant pizza.” Today, it’s one of those episodes of Star Trek that people tell you defines the entire franchise. They’re not wrong, particularly because we’re just talking about The Original Series. The legacy of this episode is beyond brilliant and set-up a wonderful tradition within the rest of the franchise; a monster story is almost never a monster story

The ending of this episode is so good, and Leonard Nimoy and Shatner play the final scenes so well that I’m actually not sure it’s cool to reveal what the big twist is. If you somehow don’t know, I’ll just say this. You can’t imagine Chris Pratt’s friendly Velicrapotrs, or Ripper on Discovery without the Horta getting their first.

3. “The Corbomite Maneuver” 

If there’s one episode on this list that truly represents what Star Trek is usually all about on a plot level, it’s this one. After the first two pilot episodes —“Where No Man Has Gone Before” and “The Cage”—this was the first regular episode filmed. It’s the first episode with Uhura and, in almost every single way, a great way to actually explain who all these characters are and what the hell they’re doing. The episode begins with Spock saying something is “fascinating” and then, after the opening credits, calling Kirk, who is down in sickbay with his shirt off. Bones gives Kirk shit about not having done his physical in a while, and Kirk wanders through the halls of the episode without his shirt, just kind of holding his boots. 

That’s just the first like 5 minutes. It just gets better and better from there. Like a good bottle of tranya, this episode only improves with time. And if you think it’s cheesy and the big reveal bizarre, then I’m going to say, you’re not going to like the rest of Star Trek. 

2. “The City on the Edge of Forever”

No more blah blah blah! Sorry, wrong episode. Still, you’ve heard about “The City on the Edge of Forever.” You’ve heard it’s a great time travel episode. You’ve heard Harlan Ellison was pissed about how the script turned out. You heard that Ron Moore really wanted to bring back Edith Keeler for Star Trek Generations. (Okay, maybe you haven’t heard that, but he did.)

Everything you’ve heard about this episode is correct. There’s some stuff that will make any sensible person roll their eyes today, but the overall feeling of this episode is unparalleled. Time travel stories are always popular, but Star Trek has never really done a time travel story this good ever again. The edge of forever will always be just out of reach.

1. “A Taste of Armageddon”

Plot twist! This excellent episode of TOS almost never makes it on top ten lists. Until now! If you blink, “A Taste of Armageddon” could resemble at least a dozen other episodes of TOS. Kirk and Spock are trapped without their communicators. The crew has to overpower some guards to get to some central computer hub and blow it up. Scotty is in command with Kirk on the surface and is just kind of scowling the whole time. Kirk is giving big speeches about how humanity is great because it’s so deeply flawed.

What makes this episode fantastic is that all of these elements come together thanks to a simplistic science fiction premise: What if a society eliminated violence but retained murder? What if hatred was still encouraged, but war was automated? Star Trek’s best moments were often direct allegories about things that were actually happening, but what makes “A Taste of Armageddon” so great is that this metaphor reached for something that could happen. Kirk’s solution to this problem is a non-solution, which makes the episode even better. At its best classic Star Trek wasn’t just presenting a social problem and then telling us how to fix it. Sometimes it was saying something more interesting — what if the problem gets even harder? What do we do then? 

The humor and bombast of “A Taste of Armageddon” is part of the answer to that unspoken question, but there’s also a clever lesson about making smaller philosophical decisions. In Star Wars, people are always trying to rid themselves of the dark side of the Force. In Star Trek, Kirk just teaches us to say, “Hey I won’t be a terrible person, today” and then just see how many days we can go in a row being like that.

What do you think are the most franchise-defining episodes of Star Trek: The Original Series? Let us know in the comments below.