Star Trek's Best Mirror Universe Episode Ever, According To Fans

One "Star Trek" Mirror Universe episode reigns supreme in the minds of fans, and it's an action-packed thrill titled "Mirror, Mirror" in "Star Trek: The Original Series" (which we ranked as the best "Star Trek" series).

Season 2, Episode 4 aired in 1967, premiering as the franchise's first-ever episode taking place in a parallel universe. The story transports audiences to a new reality where Captain Kirk (William Shatner), Spock (Leonard Nimoy), and the others' Enterprise counterparts work for the tyrannical Terran Empire. Forced to go undercover as their alternate selves in order to make it back home, the crew undergoes a tense series of events. 

Unlike the "Star Trek" episodes that have aged poorly, "Mirror, Mirror" currently holds a 9.0 user score on IMDb, the highest of the 17 franchise episodes set in the alternate dimension. Similarly, Ranker lists the episode as the top-rated Mirror Universe installment, with 46 first-place votes from fans. Marked by its sinister twist on the series' main characters, "Mirror, Mirror" was a massive hit for "Star Trek."

"Star Trek" fans have crowned "Mirror, Mirror" the best Mirror Universe installment because of its riveting plot and intricate character work. "Every action anybody takes makes sense, the characters are developed superbly, and the pacing is swift and invigorating," one IMDb user review reads. "This is quality TV writing, and if every script had been this good the series would have lasted a lot longer, I think."

Over on Reddit, "Star Trek" viewers have often shared their love for the episode. "My favorite part is how quickly Spock figures out the evil counterparts in the normal universe and how unflustered he is by all of Mirror Kirk's violent threats," a commenter pointed out, referencing one of the most memorable "Star Trek" moments. Nearly six decades since "Mirror, Mirror" premiered on TV, it still holds a reputation as one of the legendary sci-fi show's finest episodes.

Audiences who enjoy high-stakes espionage and mind-bending universe traveling can now stream "Mirror, Mirror" on Paramount+ and Pluto TV.