Must Watch Episodes from Star Trek TOS Season 2

When I originally sat down to write a list of recommended episodes from the original Star Trek series, I thought I’d be able to fit all 3 seasons in a singular post. It wasn’t until I started going back through the list of episodes that I remembered how great much of the original series is. If you can look past the lack of effects and its incredibly campy nature, there’s a lot to love about the series.

The first season of the original Star Trek pulled out a lot of stops in terms of creativity and heavy-hitting concepts. It entered season 2 with a level of popularity granted by the success of the first season. Season 2 contains some of the entire Star Trek Franchise’s most iconic episodes. It also introduced Chekov as a character in the series. (Hard to believe he was absent for the entire first season!)

But if you take a look at the season 2 episodes in rapid succession (as I did for this list), you may notice that many of them follow similar formulas, which makes the plots feel rather samey. There are a lot of powerful killer energy beings (and a lot of antimatter bombs employed to defeat them). There are many attempts to force the Enterprise crew to forever abandon their ship and live out their lives on alien planets. And there are a lot of lost or twisted Earth morals revealed among primitive civilizations.

So it was a little easier to narrow down the episodes to include on this list than the last one. Still, Star Trek season 2 is well worth your time, though I recommend starting with the episodes below.

1. Mirror, Mirror

Even if you’ve never watched a single episode of Star Trek you will probably know exactly which episode this is. It is the introduction of the Evil Goatee Universe. In short, Kirk, Dr. McCoy, Scotty and Uhura are inadvertently teleported to a mirror universe while attempting to return to the Enterprise from an away mission.

This new version of the Enterprise isn’t ruled by science, logic and reason, but brutality. Kirk even has a panel in his chambers from which he can torture other members of his crew. Here the Enterprise crew scheme and threaten each other to gain power and position. Somewhat ironically, may people believe the term Chekov’s gun refers to a scene which takes place in this episode.

No other concept in the Star Trek universe is as revisited as the mirror universe. Deep Space Nine created an entire series of side episodes that involved the characters popping in and out of the mirror universe to meet their personas. Pretty much every other Star Trek series also mentions the mirror universe in some way – even if it’s only in comics and literature.

Mirror, Mirror is consistently rated as one of the top Star Trek episodes of all time. (Though for me it still probably rates behind Miri and Taste of Armageddon.) So if you watch only one episode from season 2, make it this one!

2. The Trouble with Tribbles

Like Mirror, Mirror, the Trouble with Tribbles is one of the Star Trek franchise’s most iconic episodes. The truth is, it’s silly. Hilarious, in fact. But no other Star Trek episode has gone through so many iterations and revisits. This episode was so popular it was animated without plot changes for the Star Trek animated series. And several members of the Deep Space Nine crew revisit the events of this episode due to inadvertent time travel.

The plot can be summed up as get your pets spayed and neutered or you might end up in a similar situation. When Lt. Uhura purchases an innocent-looking ball of fluff on shore leave, it kicks off a series of hilariously unexpected events. The end is actually a tiny bit dark but, overall, you’ll probably laugh for most of the episode… Especially when Kirk gets a load of fuzz dumped over his head.

3. Amok Time

This is one of my personal favorite episodes of Star Trek in general. It’s the opening of season two and one of the first Vulcan worldbuilding episodes. This is also the first time the Vulcan Salute is seen on screen.

Spock is in a bind when this episode opens. He is undergoing the pon farr – a condition experienced periodically by male Vulcans that forces them to mate or die. It’s made clear in the episode that no one outside of Vulcans really understands much about the pon farr, and Vulcans don’t like to talk about it. Furthermore, Spock can’t mate with just anyone – he has been promised to an arranged marriage. He now has to show up and seal the deal or die trying.

Kirk disobeys orders to take Spock home. But when they arrive, they find that Spock’s intended has chosen another. I don’t want to say too much more because this episode is a delight to experience. And just to prove I know how to pick ’em… This is another episode that constantly ranks on top 10 lists for the Star Trek original series.

4. A Private Little War

My favorite Star Trek episodes consistently fall into two categories: character episodes (like Amok Time) or moral quandary episodes. To me, the heart of Star Trek has always been dealing with difficult moral questions that don’t necessarily have easy or straightforward answers. This episode certainly delivers on the latter.

Kirk and his crew are visiting a primitive planet when they notice something unexpected… firearms. As they investigate further, it soon becomes clear that Klingons have recently visited the area and Kirk suspects that they have been supplying some of the planet’s villagers with weapons.

This leaves Kirk in a difficult position. The federation forbids interfering with the development of primitive species. But if Kirk obeys the prime directive, the Klingons (who do not ascribe to the same philosophy) will be able to shape the future of the species. Caught between a rock and a hard place, Kirk must decide whether to walk away or balance the playing field.

5. The Ultimate Computer

Man versus machine has been a theme in sci-fi from its inception. Will computers eventually surpass human capabilities, making us redundant? In this episode, the Enterprise crew test out a new computer known as the M-5. It has been designed to handle all ship functions without human assistance and even make command decisions.

Fans of Macross Plus or the movie Stealth might recognize pieces of this episode’s plot. When left to its own devices, the M-5 turns out to be unpredictable and difficult to control. It also turns out its programming may have been slightly supplemented by human brain patterns.

This is another one of those episodes that proves why Kirk is such a great commander while also asking questions about our computer-filled future. And considering how much we rely on technology these days, I think the subject matter is as relevant as ever.

6. Obsession

If the previous episode shows Kirk at his best, then this episode perhaps shows Kirk at his worst. When the crew encounter a powerful nebulous being that kills with ease and without remorse, Kirk recognizes it as a being that killed a crew he used to serve on.

Throughout the episode, Kirk confronts not only his nemesis, but also his past. He believes that a moment of hesitation back then may have cost more people their lives and is determined to redeem himself. But his obsession clouds his judgment, proving that he is also fallible.

I don’t want to spoil the ending, so you’ll have to watch to figure out if Kirk comes to terms with the past by dealing with the present.

Honorable Mention

I was tempted to include I,Mudd on this list entirely because I love the character. Harry Mudd is something of a hapless space pirate. He gets himself wrapped up in schemes that inevitably attract and spill over to the Enterprise crew. He’s first introduced in season 1 in the episode called Mudd’s Women, and he appears again in similar trouble in I,Mudd. There are no great revelations in the Mudd episodes, but they are pretty funny.

For something that plays on a bit of Earth folklore, check out Wolf in the Fold, which suggests that Jack the Ripper might not have been human but, in fact, an alien entity. The killer’s ultimate fate is in the hands of the Enterprise crew.

If you’re a fan of Star Trek First Contact, check out Metamorphosis to learn the final fate of Zefram Cochrane, the famous inventor of the warp drive.

And finally, for a tad more world and character building, check out Journey to Babel. This episode introduces the Andorians. It also introduces Spock’s parents and their somewhat complicated relationship.