I assumed that “Mirror, Mirror” would be TOS’s first foray into the subject of parallel universes, but apparently, I was wrong: “The Alternative Factor” is not, as I initially suspected, some sci-fi parable about false alien prophets and resurrection, but a story about the dire consequences of meeting your own parallel self.
I’d really like to say it’s a good story about meeting your own parallel self, but, well. I’ve never been much of a liar.
DISCLAIMER
There will be SPOILERS for this episode and probably the Star Trek franchise in general. You’ve been warned.
WHAT GOES DOWN, BASICALLY
The Enterprise is scanning some planet when they appear to hit some sort of rift or crack in spacetime. Apparently, everything in the solar system almost blinked out of existence for a second there, which is obviously concerning. A new life sign on the planet directs our heroes to a dude with a ludicrously sad fake beard. The dude insists he needs their help and then, very theatrically, collapses.
Dude’s name turns out to be Lazarus, and he’s been chasing after a humanoid “thing” that destroyed his whole civilization. He wants the Enterprise’s dilithium crystals for his holy cause of vengeance, but Kirk’s all, “NOPE, we need those to power the ship.” Weird shit keeps happening, too, that makes Kirk alternatively trust and doubt Lazarus’s word. The universe keeps blinking, for lack of a better term, and Lazarus keeps getting into multiple fights with some mysterious humanoid shape. (Significantly, the special effects don’t allow us to see who is who here. Rest assured, the special effects will be discussed in more detail later on.) Lazarus’s wounds also seem to disappear and reappear at random, and his behavior changes from relatively collected to downright histrionic. Then the dilithium crystals do get stolen. Also, the planet Lazarus claims to be from doesn’t actually exist.
Lazarus explains this last by insisting that he’s a time traveler. The thing he’s chasing is a time traveler, too, and must have stolen the crystals. But, as we soon discover, only half of this is true. Lazarus has been fighting Parallel Universe Lazarus in a sort of in-between pocket dimension (or negative magnetic corridor). Lazarus wants to kill PUL pretty much just for existing, but if the two should ever meet in the “matter” universe (ours) or the “anti-matter” universe (PUL’s), total annihilation of everything ever could occur. So, that’s bad.
Lazarus, who totally doesn’t give a shit about annihilation, sabotages the Enterprise and goes back to the planet with different stolen crystals. Kirk manages to transport himself to the anti-matter universe, where he meets PUL. PUL’s tragic-ass plan is to capture Lazarus in the corridor and be stuck there fighting him forever. The universe is saved, but Kirk, appropriately, is bummed out by PUL’s grim fate. This is the rare episode that doesn’t end with some light banter between him and Spock.
MY TAKE
Honestly, the idea of this episode is pretty cool, like, I enjoy the basic arc of it, right down to the tragic end. Also, it’s nice that it’s not ridiculously obvious what’s going on from the get-go. “Errand of Mercy” is undoubtedly a better episode, for example, but I wasn’t watching “The Alternative Factor” whilst chanting, “Jesus Christ, they’re omnipotent beings who don’t need your help, get a fucking clue” for forty minutes straight. So, that’s lovely.
Unfortunately, I’m afraid I don’t have much else positive to say. This episode is a confused, conflicting mess, featuring characters who make baffling decisions just to keep the plot moving and a ridiculously over-the-top performance by Robert Brown as Lazarus. (I know he was a last-minute replacement, but goddamn.) I mean, as PUL, he’s fine, but Lazarus himself? He’s pretty excruciating to watch. His awful fake beard is just as excruciating, particularly because it keeps changing size–not, as we first assumed, as a clue that Lazarus is secretly two people, but just because whoever applied it kept doing it so damn inconsistently.
And those special effects? Man. It’s not the actual effects I take issue with–this show is old, after all–but how often they use them. For instance, here is one of the many, many blue corridor battles. (This clip also includes Lazarus yelling, “Kill! Kill! Kill! Kill! Kill!” if you don’t believe me about the bad acting–though, to be fair, that’s not exactly stellar dialogue to work with, either.)
We see this corridor, this rip in space, and this goddamn same spinning newsreel effect a bunch of times in this episode, and I’m here to tell you, it gets old quick. Not to mention, if you’re not feeling 100% (which as of this typing, I’m not, though I expect I’ll feel fine by the time this review is posted), all this spinning is . . . not awesome. Usually, that kind of shit doesn’t bother me, but today? Ugh.
Overall, this is a tragic episode that’s nearly impossible to take seriously. Let’s just say I’m not exactly surprised to find out “The Alternative Factor” is not one of TOS’s more beloved episodes.
RANDOM ASIDES
One genuinely exciting thing about “TAF” is the presence of Lt. Charlene Masters (Janet MacLachlan), a black female Starfleet officer (Uhura isn’t the only one!) who has several lines in this episode, including one about the Enterprise’s shitty coffee. And she’s not some random yeoman, either; she’s actually an engineer and appears to have some degree of authority, which is honestly pretty cool.

I’m not entirely sure why an engineer is dressed in science blue, but that’s a mystery for another day.
Apparently, Masters was originally supposed to have a romantic relationship with Lazarus, a storyline that likely got axed because the studio was too nervous about an interracial romance. I know I should be angry about that–and I am, a little–but if I’m being honest, I’m also pretty relieved because it sounds like this “romance” would’ve been of the Khan/McGivers variety, and that shit was gross as hell. Masters is so much better than that. (Better than Lazarus, too.) I really wish she wasn’t a one-episode character.
Sulu Watch: Sulu and Scotty–shockingly, oh, so shockingly–are not in this episode. I’ve decided that they’re secretly conducting a drinking game for all these parallel universe shenanigans: take a shot whenever the solar system blinks, take a shot whenever Lazarus screams about something so loud you can hear him through the walls, etc. Your call on who wins.
About 14 minutes into the episode, there appears to be a big red sign in the background of the bridge that says . . . I’m not sure. EMERGENCY ALERT, maybe? Er. Has that ever been there? Has that always been there? Have I really just not noticed it until 28 episodes in?
The whole time travel nonsense is just weird. Like, I get Lazarus is lying and all, but because it comes so late in the episode and the truth comes out literally in the next scene, it feels less like a misdirect and more like a dropped plot thread.
It’s rare that I critique the science in anything because I’m such a one-sided English/History person, it’s not even funny, but I’m suspecting the science on display in this episode is . . . not stellar? Certainly, I suspect it’ll contradict with the science in next season’s “Mirror, Mirror.”
Very early in the episode, the top brass at Starfleet decide that the initial rift in spacetime might be a “prelude to invasion.” Which, I mean. I guess it could’ve been? But there’s absolutely zero evidence for such a hypothesis, like, we’re jumping from Point A to Point Q here right quick.
At one point, Kirk actually does the “fact” argument. You know, “Fact, this suspicious thing happened, fact, that suspicious thing happened,” etc. This isn’t really significant, mind you; I just thought it was funny.
Look. We’ve gotta talk about Bones, cause, I like him and all, but the boy fucks up this episode. At first, I had sympathy for him: he tells Kirk about Lazarus’s disappearing head wound, but by the time Kirk sees him, Lazarus is all cut up again. Kirk immediately decides that Bones is wasting his time, and I’m like, uh, no, there is clearly a bunch of weird shit going down here. I think you can trust your CMO isn’t playing a practical joke while the universe is threatening to blink out of existence. But then. BUT THEN. Bones insists that Lazarus doesn’t need to have a guard posted, even though the dude’s credibility is seriously shot by this point (not to mention he’s been agitated and could potentially hurt himself). Bones straight up says, “Well, don’t worry. He’s not going anywhere, not this time.” He then immediately walks out of the room, leaving Lazarus alone to tumble out of bed and take off, and the medical-adjacent professional in me is just incensed. Bones absolutely deserves to get demoted for this shit.
I actually like a good handful of the dialogue. I mean, obviously not the “kill kill kill” part. But this line by Spock, for instance: “Jim, madness has no purpose. Or reason. But it may have a goal.” That’s a decent line. I’m also rather fond of this exchange between Kirk and Lazarus:
“How did the beast get on board?”
“He did. Isn’t that enough?”
“No!”
Still, I do think Spock will have to win this one, albeit for a different bit of dialogue:
LINE OF THE EPISODE
“I fail to comprehend your indignation, sir. I have simply made the logical deduction that you are a liar.”