Star Trek: Mirror, Mirror

Episode: "Mirror, Mirror"
Series: Star Trek: The Original Series
Season 2, Episode 4
Original Air Date: October 6, 1967

via Memory Alpha

Is high concept science fiction redundant?

"Mirror, Mirror" poses the question, what if the benevolent United Federation of Planets were an evil empire instead?  Through a transporter malfunction, Kirk, McCoy, Scotty and Uhura find themselves in a parallel universe, upon an Enterprise where treacherous ambition is the basis of society.  This Mirror Universe has been revisited in spin-off Trek series and other licensed material in the years since, an important check on the moral compass that guides the franchise.  Besides, it's just plain fun to see Evil Kirk, Evil Sulu and, best of all, Evil Spock with the wicked goatee.

This was my favorite episode in a while, partly for the basic fun of the parallel universes but also for the fact that all seven principal characters have meaningful roles in the story.  So much of the original series focuses on the dynamic between Kirk, Spock and Bones - and for good reason.  Judgment balancing logic versus emotion is the heart and soul of Trek.  But the side characters are often greatly diminished at the expense of the big guns.  Scotty, Uhura, Sulu and Chekov all play vital parts in "Mirror, Mirror" and the story is better for them.

*****

via Memory Alpha

Barbara Luna played the role of Lt. Marlena Moreau, a Lady Macbeth-type character who is Kirk's ambitious lover in the Mirror Universe.  She was born March 2, 1939 in New York City.  She started as a child actor on Broadway, performing as the daughter of Ezio Pinzo in the original stage production of South Pacific.  She made her film debut in 1958's The Tank Batallion.  She has over 500 television appearances to her credit, including multiple episodes of Zorro, Mission: Impossible and Buck Rogers in the 25th Century among others.