Star Trek (1966–1969)
32 user 7 critic

The Alternative Factor 

Existence itself comes under threat from a man's power-struggle with his alternate self, with the Enterprise's strained dilithium crystals presenting his key to a final solution.


Gerd Oswald


Don Ingalls, Gene Roddenberry (created by)

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Episode complete credited cast:
William Shatner ... Capt. Kirk
Leonard Nimoy ... Mr. Spock
Robert Brown ... Lazarus
DeForest Kelley ... Dr. McCoy
Janet MacLachlan ... Lt. Charlene Masters
Nichelle Nichols ... Uhura
Richard Derr ... Barstow
Arch Whiting ... Assistant Engineer
Christian Patrick Christian Patrick ... Transporter Chief
Eddie Paskey ... Lesley


While investigating and scanning an uncharted planet, the Enterprise and its quadrant of space are subjected to a violent force that seems to cause a 'blinking out' of everything near them. When the scanners resume, where once there was no life on the planet, now there is one life sign. Kirk, Spock and a security force beam down to investigate and find a man named Lazarus who collapses and is brought aboard the Enterprise for treatment. To complicate things further, the initial phenomenon almost totally drained their dilithium crystals. Starfleet and Kirk suspect this phenomenon could be a prelude to invasion. While interrogating Lazarus he tells Kirk that he's locked in a struggle with another being who is 'anti life' and is behind the phenomenon. The disruptions continue to occur and the ship's situation grows worse. Written by tomtrekp

Plot Summary | Plot Synopsis


TV-PG | See all certifications »


Official Sites:

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Release Date:

30 March 1967 (USA) See more »

Company Credits

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Technical Specs


Sound Mix:




Aspect Ratio:

1.33 : 1
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Did You Know?


This takes place in 2267. See more »


Kirk wants "every inch" of the planet searched, but Starfleet is on the metric scale. See more »


Spock: What of Lazarus?
Capt. Kirk: And what of Lazarus?
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Crazy Credits

The closing credits are set against a combination background of stills from that episode and previous episodes. See more »


Referenced in Galaxy Quest (1999) See more »


Theme From Star Trek
Written by Alexander Courage
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User Reviews

A Third-Season episode that ran in the First
2 December 2007 | by FlyByNight32See all my reviews

Given the meager quality of a good part of the third season, that's what this feels like.

I can live with a dimension-crossing paranoid maniac. I can live with him being a threat to the immediate area, several solar systems, maybe even the galaxy.

But the universe?

I don't even want to talk about the basic flaws in the whole matter-antimatter plot point, but 150-200 lbs of matter and antimatter wouldn't take out the universe.

The dilithium bit I can live with. They were still getting their feet wet on the technology, deciding what exactly this and that could and couldn't do. I just grind my teeth a little during those scenes.

The thing I just absolutely can't buy is the solution. Toss Laz A in with Laz B and let them duke it out for eternity?

The ship has phasers. Take out his ship. No ship, no doorway. And if you're afraid he might build another one, you have two choices.

#1 - Lock him up for the rest of his natural life, doped out on thorazine to the gills. #2 - You've got a phaser in your hand, he doesn't, and what happens on Planet Vegas stays on Planet Vegas.

Still, though, not as bad as Spock's Brain. Or Wink of an Eye. Or Spectre of the Gun. Or.... well, you get the idea.

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