Television history is littered with shows that flared bright and burned out before they could find their footing. Star Trek almost met that fate. But then came the second season. When people talk about Star Trek TOS 2, they aren't just discussing a block of episodes; they're talking about the moment Gene Roddenberry's "Wagon Train to the Stars" actually became the cultural monolith we know today. It was messy. It was brilliant. It was occasionally ridiculous.
Think about the stakes for a second. In 1967, NBC wasn't exactly sold on the idea of a high-concept sci-fi show. The ratings were shaky. The budget was being squeezed by the studio, Desilu. Yet, during this specific stretch of twenty-six episodes, the production team managed to introduce the Romulans, the Klingons (in their more recognizable adversarial role), and the concept of the Vulcan "pon farr."
It’s where the "Big Three" dynamic of Kirk, Spock, and McCoy finally solidified. Before this, they were still figuring out if Spock was too alien or if McCoy was just a grumpy background character. By Star Trek TOS 2, the chemistry was chemical. It was undeniable.
The Creative Pressure Cooker of 1967
The second season kicked off with "Amok Time." Honestly, if that episode had failed, the show might have died right there. It was the first time we saw Vulcan. It gave us the iconic music cue that every parody has used for fifty years. More importantly, it established that Spock wasn't just a walking computer; he was a character with a biological and cultural burden. Theodore Sturgeon wrote that script, and his influence—alongside other giants like Harlan Ellison and Richard Matheson—is why this season feels so much "heavier" than the first or third.
Production wasn't easy. Desilu, the studio owned by Lucille Ball, was in the process of being sold to Paramount. This meant the accountants were watching every penny. You can see it on screen. They started reusing sets more often. They leaned into the "planet that looks exactly like Earth history" trope—Nazi planets, gangster planets, Roman planets—partly because the costumes were already sitting in the studio wardrobe department.
Despite the penny-pinching, the writing remained sharp. Mostly. For every "Mirror, Mirror," you had a "The Gamesters of Triskelion," which is basically just Kirk fighting guys in capes for an hour. But even the "bad" episodes of Star Trek TOS 2 have a certain charm. They were swinging for the fences every single week.
The Arrival of Chekov and the Youth Movement
One of the biggest shifts in this era was the introduction of Pavel Chekov, played by Walter Koenig. Legend has it the Soviets complained that there were no Russians on the ship, but the reality is more pragmatic: the producers wanted to appeal to the "Monkees" demographic. They gave Koenig a moptop wig and told him to act youthful.
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It worked. Chekov added a different energy to the bridge. Suddenly, the Enterprise felt like a global (and intergalactic) vessel. It wasn't just a bunch of American guys in space anymore. You had Sulu, Uhura, and now Chekov. For 1967, that was a radical statement. It still is.
Episodes That Changed Everything
If you’re looking at why Star Trek TOS 2 is the peak of the original run, you have to look at "The Trouble with Tribbles." It’s the ultimate proof of concept. It showed that Star Trek could do comedy without losing its soul. David Gerrold, who was just a kid at the time, wrote a script about reproductive rates and ecological disaster disguised as a story about furry balls that purr. It’s genius.
Then there’s "Mirror, Mirror." It gave us the "Evil Spock" with a goatee, which has become a universal shorthand for an alternate reality. This episode explored the idea that the only thing separating the Federation from a fascist Empire is a few different choices. It was dark. It was cynical. It was exactly what 1960s audiences needed to see while the Vietnam War was escalating on their evening news.
The Forgotten Struggles of Gene L. Coon
While Roddenberry gets the lion's share of the credit, most Trek historians—like Marc Cushman or Herbert Solow—will tell you that Gene L. Coon was the real hero of the second season. Coon was the showrunner, essentially. He’s the one who invented the Klingons. He invented the United Federation of Planets. Before Coon, the Enterprise was just a ship out there on its own. He gave it a government. He gave it a context.
Coon eventually burned out. The pressure of turning out a script every week while fighting with Roddenberry and the network was too much. He left toward the end of the season, and many fans argue that’s when the "golden age" ended. But the foundation he laid during the second season is what every Star Trek show since has built upon.
The Logic of the "Star Trek TOS 2" Budget
People often joke about the cheap sets. "Look, another cave made of painted Styrofoam!"
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But consider the context. In 1967, $190,000 per episode was a lot of money, yet it was barely enough to cover the ambitious scripts they were writing. To save money, they filmed "bottle episodes" where everything took place on the ship. "The Doomsday Machine" is a perfect example. It’s tense, it’s terrifying, and a huge chunk of it is just William Shatner and William Windom talking in a dark room or looking at a viewscreen.
They used lighting to hide the fact that they didn't have money for elaborate sets. Director Joseph Pevney was a master of this. He used "noir" style lighting—heavy shadows, sharp colors—to make a plywood set look like an alien fortress. It gave the show a distinct visual identity that modern, high-budget CGI often lacks.
Why Discovery and SNW Keep Going Back
There’s a reason Strange New Worlds and Discovery keep mining this specific era for content. The aesthetic of the second season—the primary colors, the mini-skirts, the brutalist architecture—is the "true" Star Trek. When fans think of the show, they don't think of the pilot "The Cage." They think of the vibrant, high-contrast world of Star Trek TOS 2.
It’s the season where the uniforms were perfected. It’s where the phasers and tricorders became iconic props. It’s the season of "Journey to Babel," which introduced Spock’s parents, Sarek and Amanda. That episode alone established the Vulcan-Human conflict that has fueled Spock’s character for sixty years. You can't have the 2009 reboot or the Picard series without the heavy lifting done in this season.
Dealing with the Controversies
We have to be honest. Some of this season hasn't aged perfectly. "The Ultimate Computer" is a great look at AI taking over jobs—very relevant today—but "The Apple" is... well, it’s about a literal snake-god-computer and people wearing blonde wigs. It’s a bit much.
And then there’s the treatment of female characters. While Uhura was a trailblazer, many of the guest actresses were relegated to "love interest of the week" roles. It was a product of its time, but it’s a valid critique. Fans often debate if the show was truly progressive or just pretending to be. Usually, the answer is somewhere in the middle. It pushed boundaries where it could, but it was still beholden to the standards of 1960s network executives who were terrified of offending anyone in the South.
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Actionable Insights for Fans and Collectors
If you’re diving back into this era, don't just watch the episodes in order. Context matters.
- Watch the "Production Order" vs "Airing Order": Sometimes the air dates make no sense. Watching them in the order they were filmed gives you a better sense of how the actors were developing their characters.
- Look at the Background: Season 2 is famous for its "background" actors who became legends, like Eddie Paskey (Lt. Leslie). He appeared in almost every episode, sometimes as different characters. It’s a fun meta-game to play.
- The Blu-ray Choice: If you’re watching on physical media, get the versions that allow you to toggle between the original 1960s special effects and the 2006 CGI updates. The CGI is "cleaner," but the original model work by Greg Jein and the team has a soul that can't be replicated.
- Read "The Making of Star Trek": Written by Stephen E. Whitfield during the production of the second season, this book is the "bible" for how the show was actually put together. It was published in 1968 and captures the chaos of the set perfectly.
The Enduring Legacy
Star Trek TOS 2 ended with "Assignment: Earth," which was actually a "backdoor pilot" for a different show Gene Roddenberry wanted to make. It featured Gary Seven and a cat. It’s a weird way to end a season, but it perfectly encapsulates the era: experimental, slightly desperate, and full of big ideas.
Ultimately, this season proved that sci-fi could be more than just monsters and ray guns. It could be about philosophy. It could be about the human condition. It could be about three friends trying to do the right thing in a galaxy that didn't always want them there.
The second season is where the soul of the franchise was forged. Without it, Star Trek would be a footnote in TV history instead of the legend it became.
Next Steps for Enthusiasts:
To truly appreciate the craftsmanship of this era, compare the script for "The City on the Edge of Forever" (Season 1) with "Mirror, Mirror" (Season 2). You'll notice a shift from pure "hard sci-fi" toward a more character-driven "social sci-fi" that defines the Trek brand. Check out the Star Trek: The Original Series remastered collections on streaming services, but pay close attention to the sound design—the ambient hum of the bridge was specifically engineered in Season 2 to create a sense of "technological comfort" for the viewer.