“I do not threaten, Captain. I merely state facts. I have found you to be an excellent officer. Our missions together have been both successful and profitable; however, I shall not permit your aberrations to jeopardize my position.”
I’ll jump in here with “Mirror, Mirror”, undoubtedly the most sequelized episodes of TOS with five episodes of Deep Space 9 taking place there, two episodes of Enterprise, and (apparently) seven episodes and counting of Star Trek: Discovery. Plus a metric crap-ton of novels and comics.
I had absolutely forgotten more than I remembered about this episode, from the midriff-bearing pirate costumes (Spock got an ascot… or perhaps a cravat…), to the personal mercenary details of the officers, to Spock’s threat to Sulu that his death would be avenged by shadowy Vulcan ninja “operatives”.
The big thing that struck me was how very fleshed-out the Mirror-universe actually was: from the kill orders being dictated from High Command, to the implications that the Empire had over-extended itself, to the horrific command record of the “Mirror Kirk”, it’s obvious that Jerome Bixby had a great time coming up with an evil version of Roddenberry’s Starfleet.
Everyone got to chew a little scenery in this episode, but Nichelle Nichols really got to shine a bit more here than in many other episodes, following up on her singing in the previous week’s episode. Although it seems a little sexist, I really liked the early scene where she emotes some doubt about going alone to a bridge full of evil space-barbarian/pirates, and Kirk gives her a little pep-talk: “You’re the only one who can do it!” That made the later scene of her toying sexually with Mirror Sulu even more powerful.
Walter Koenig didn’t have too much to do in this episode, but his bout of screaming in “The Booth” reminded me viscerally of his screaming in “Wrath of Khan”.
The final scene with “Marelena” being introduced to the “real” Kirk always kind of rubbed me the wrong way, even as a kid. It’s one thing for the Mirror-universe to have “Captains’ Women”, but I didn’t like the impression that they gave that Kirk was immediately going to start going after this poor young junior officer simply because the alternate-world version of her was sleeping her way to the top.
Some little trivia points, both about the costumes:
First, Desilu/CBS regulations forbade showing female belly-buttons during prime-time, but several of the female parts had bared midriffs. In most scenes, the sash would cover the belly-button, but Nichols’ showed hers in several scenes… this was apparently accomplished by treating the on-set censor to lunch, then filming those scenes when he was eating.
Second, the Mirror-versions of the uniforms had all sorts of little adornments, from sashes to cravats, to fringed epaulets. But they also had a bunch of random pins and decorations around their Starfleet symbol. As noted earlier, George Takei was filming The Green Berets during a portion of Season 2, and one of Mirror-Sulu’s pins is that of an ARVN Captain… the rank his character has in that movie.