One of the aspects of the Star Trek series that I always enjoyed was the continuity of plot lines across series. The mirror universe is one of the most well structured examples of this.
In the original series, Captain Kirk, Scotty, Bones,and Uhura, end up switching places with their doppelgangers from the alternate universe due to a transporter accident. Of course, in the “Mirror” universe everyone is evil, the federation is an empire, women are scantily clad, and men wear beards.At the end of this episode, just before the happy ending where everyone goes home, ‘real’ Kirk encourages mirror Spock to recognize the tyrannies fail but freedom is forever, and the logical thing to do is reform.
Flash forward to the Deep Space Nine series (DS9) produced 3 decades alter, set a century after, the original. In the second season, Major Kira Nerys and Doctor Julian Bashir get trapped in the Mirror universe due to a shuttle engine leak while traversing a stable wormhole.
This time there is no switch, and they meet their counterparts. Major Kira’s Mirror is a petty tyrant, and the Chief O’Brien’s is a slave in an ore processing facility under her command. The Doctor’s Mirror is not seen. It seems Kirk did have influence on mirror Spock, who in turn did change the empire into a peaceful federation. The result, however, was an uprising by the formerly oppressed who then turned the humans into slaves and built their own empire. Now led by the Klingons and Cardassians, with the Bajorans playing a significant role.
I found this attention to detail impressive. Not only honoring the roots of Roddenberry’s creation, but also maintaining the story line for the audience. They could have developed a new alternate universe, with their own rules, but the authors chose to develop the story organically.
DS9 devoted 5 episodes to the Mirror universe, which gave them time to develop the characters and plot. Instead of a flat, “Bizzaro World” where the characters are all just opposites, we find the characters have similar root personalities that have developed differently due to circumstance. Similar to identical twins seperated at birth and put in different cultures.
So the Chief is still mechanically inclined, but never received Federation training. Kira is still in the military, but instead of being a resistance fighter she is a tyrant. And, despite the influence of Kirk, the mirror universe remains a place of oppression.When Bashir tells Mirror O’Brien (Smiley) that in the other universe he is a “Chiefof Operations” it blows his mind. The idea that his life could have been something other than slavery rocks the foundations if his identity. Setting in motion a series fo events that will alter the Mirror Universe.
Captain Sisko’s Mirror is a privateer serving the tyrant Kira in exchange for not working in the mines. It is also insinuated that he is her sex slave, as are several other females and males. Influenced by the crossover characters “Smiley” (O’Brien’s Mirror) and he become the leaders of a human revolt against the empire. And the struggle for freedom continues.
In the prequel series, Star Trek: Enterprise, during the last season they had an episode entirely within the Mirror Universe that showed how the Federation got turned into an Empire by the Mirror Jonathon Archer. A paranoid megalomaniac bent on instilling order and security to the galaxy, resulting in neither. He is assassinated by his consort, Sato, before he can even where the crown, who then declares herself Empress.
A story which, on the surface, appears to be a political soap opera in space, is in fact a parable about the illusion of control, and the influence of circumstance.