(written from a Production point of view)
In the mirror universe, the destruction of Enterprise leaves the crew stranded aboard the USS Defiant, a ship from a future parallel universe where a governing body known as the United Federation of Planets reigns, inspiring T'Pol to speak out against the tyranny of the Terran Empire. (Part 2 of 2)
On the bridge of the USS Defiant – having just witnessed the destruction of the ISS Enterprise by the Tholians – Commander Archer supervises Chief Engineer Tucker, T'Pol, and Major Reed, as the team desperately try to escape from a Tholian drydock that holds the Defiant. Even though they manage to shake the starship free from the facility's docking clamps with the ship's deflector shields, six Tholian ship approach and speedily construct an energy net over the opening of the dock, effectively barring the Defiant's escape.
With T'Pol's assistance, Tucker manages to restore power to the Defiant's weapon systems from the bridge's engineering station. The ship then blasts its way out of the dock, destroying half of the Tholian ships in the process and continues maneuvering away, firing aft photon torpedoes at the Tholian facility while departing. Reed detects escape pods from Enterprise, so Archer orders that they be brought aboard.
As the Defiant continues on impulse power, Archer confers with his officers, including Doctor Phlox and Hoshi Sato, in the ship's briefing room. He demands that Tucker carry out the difficult task of restoring the advanced ship's warp drive, and T'Pol suggests using the expertise of the alien slave workers aboard to do so. Archer implies an agreement with T'Pol's recommendation. Although he plans that the ship will rendezvous with the Terran Empire's assault fleet, T'Pol argues that they are unprepared for battle. Archer insists on his plan and dismisses the other officers, but ensures T'Pol stays behind. He is furious that she betrayed him while aboard Enterprise. Now that Captain Forrest is dead and T'Pol finds herself threatened by Archer, she pledges allegiance to her new commanding officer, who claims the only reason she is still alive is that he needs her to help run the Defiant. Finally, after threatening her with death if he hears so much as a rumor that she's working behind his back, he angrily dismisses her.
Hoshi Sato later arrives at the captain's quarters and is amused to find Archer proudly adorned in a tunic belonging to the Defiant's former captain. After discussing the uniform, Archer tells Sato about the parallel universe that the Defiant is from, having reviewed the ship's databanks. While she pours him a green drink, he says that the other universe has no Terran Empire but that Earth instead is a founding member of the United Federation of Planets. Archer and Sato humiliate one another by showing each other the service record of the other's counterpart, Sato finding that Archer's duplicate was a highly successful Starfleet officer. Archer finds difficulty with accepting that his own counterpart was so instrumental in the Federation's founding. Sato tries to distract Archer with thoughts of his own promising future but, when she mentions that Starfleet will have to give him a command of his own, Archer declares he already has that – the Defiant.
At a vertical Jefferies tube, Tucker is irritated by Ensign Kelby reporting that a pair of plasma regulators have recently gone missing from the tube's interior. Tucker threatens Kelby to find the regulators, or be made responsible for the Defiant's inability to go to warp. After Tucker hurries away, Kelby climbs into an access tunnel above, hearing strange rattling. He finds one of the regulators lying on the floor but is pulled headfirst into a Jefferies tube directly above him.
On the bridge, Phlox reports to Archer that evidence regarding Kelby's death indicates the killer was a large reptilian. T'Pol, Reed, and Phlox discuss the reptilian. Tucker arrives and irritably comments that, without the plasma regulators, the ship is stuck at impulse, indicating – as T'Pol deduces – that the saboteur was well-acquainted with the ship's systems. Reed enthusiastically approves with Archer ordering him to bring one of the alien slaves to the briefing room.
There, Archer brutally interrogates a blue-skinned alien, who fears the reptilian will kill him and is therefore initially tight-lipped. Archer pressures the slave by pushing a phaser into his neck, threatening to disintegrate him with the weapon. This eventually makes the alien divulge information about the reptilian saboteur – a slave-master named Slar who was responsible for gutting the ship and whose species is Gorn.
On the bridge, Reed shows Archer a schematic of the Defiant on the viewscreen and updates him on the search for Slar, who recently escaped from Reed's MACOs. Archer sees a hallucination of his counterpart from the Federation universe, who criticizes the lengthy search effort and boasts about how he handled a similar situation. A frustrated Archer directs Reed to form an assault team that Archer himself will lead. From the communications station, Sato detects Slar but cannot pinpoint his location. Archer contacts the Gorn but is unwilling to negotiate the return of the plasma regulators in exchange for allowing Slar to leave in a shuttlecraft. Eventually, Slar abruptly ends the transmission. Archer reminds Reed to form the assault team and explains to T'Pol, as he heads off the bridge, that he is skeptical of the Gorn's sincerity.
Inside a turbolift, Archer's hallucinatory double reappears, whispering to him that defeating Slar will finally earn Archer the respect he deserves.
Archer later leads the assault team – including Reed and four MACOs – through the ship, first heading up a vertical Jefferies tube and into an access tunnel. Reed and two of the MACOs fall victim to a trap, however, and are downed by a remotely triggered explosion. Contacting T'Pol on the bridge, Archer learns of the Gorn's whereabouts and tells her to standby with that deck's environmental controls.
He and the remaining MACO near the Gorn's location silently search a corridor that is strewn both with exposed internals of the ship and with the bodies of several deceased officers. Without noticing Slar, Archer passes directly beneath the Gorn. He gives the MACO an all-clear signal, moments before Slar plummets down on Archer, causing him to drop his phaser. As he and the MACO assault the Gorn, it scratches Archer's torso before turning its ferocious attention on the MACO, who Slar picks up and slams into a bulkhead. The Gorn approaches Archer as he quickly contacts T'Pol, instructing her to increase a certain section of the gravity plating. Her doing so drags the Gorn to the deck. Joined by two MACOs from a nearby turbolift, Archer repeatedly shoots the Gorn 6 times, killing Slar.
- "Defiant starlog, January 18, 2155. We've recovered the missing engine components and I've ordered a course to rendezvous with the assault fleet."
As the Defiant proceeds at warp, T'Pol and Phlox sit together in the officers' lounge. Phlox reveals to a curious T'Pol that Reed could just as likely die as survive and that he himself has been researching classical literature of both universes. With the exception of the consistently grim playwright Shakespeare, Phlox has a lowly opinion of the other universe's stories, finding the characters to be weak and compassionate. T'Pol begins to speak of the Federation's equality but Phlox fears the danger that the crew could learn such discoveries. Their conversation is interrupted by a call to battle stations.
Meanwhile, the NX-class starship ISS Avenger rushes out of a debris field, under attack by four rebel vessels in pursuit. The Avenger is fighting a losing battle, with Admiral Black assuming command from a dead captain. However, the Defiant soon arrives and speedily dispatches three of the rebel ships, despite T'Pol trying to dissuade Archer from destroying a Vulcan cruiser. He leaves an Andorian ship to warn the other rebels of the mass destruction and then contacts Admiral Black, who is puzzled by the absence of Enterprise. Archer says the situation will take time to explain and invites the admiral aboard the Defiant.
Returning from a tour of the ship, Archer and an impressed Black later enter the briefing room, accompanied by Sergeant Mayweather, the Avenger's Vulcan second-in-command (Soval) and a guard of the admiral's. As the admiral refuses to grant Archer a battlefield commission to captain of the Defiant and Archer is teased by an illusory reappearance of his own duplicate, he insists that he is already a captain and – immediately after Mayweather kicks the admiral's guard to the deck – Archer disintegrates Black with a phaser.
With Avenger and the Defiant traveling side-by-side, officers from both ships are gathered in Avenger's launch bay and watch Archer make a dramatic spiel, gradually moving from a walkway above the bay to a kneeling position atop a shuttlepod. He lengthily criticizes Starfleet Command for having allowed the recent annihilation of the assault fleet and rallies the officers to his cause against Starfleet Command, proposing that they utilize the Defiant's advanced capabilities.
Later, T'Pol and Soval have a conspiratorial meeting in the latter Vulcan's quarters. Soval remarks that T'Pol's use of a Vulcan salute, upon her arrival, is socially hazardous. She confirms that he read about the Federation, from the Defiant's historical database. Fearing that Archer will decimate the Vulcan species and their homeworld, T'Pol appeals for Soval to help her betray Archer, suggesting that she acquire the Defiant's schematics before giving them to the rebels. Soval at first argues against her and is alarmed by her announcing that she will destroy the Defiant but he eventually acquiesces to her intentions.
Meanwhile, Archer and then Sato – the captain's woman – sit up from the bed of the captain's quarters, which are now darkened. Archer worries that his senior officers, particularly T'Pol, doubt that he can succeed. Attempting to reassure him, Sato suggests disposing of T'Pol, now that the Defiant is operational. Archer suddenly reveals he is intending to transfer all the non-Humans off the ship but Sato reminds him that Phlox is one of those aliens. As the couple begin to passionately caress each other, Archer accepts that Phlox can remain aboard, as his species are not rebels, and Sato wonders what will be required in the role of the Emperor's consort, to which Archer says she seems to have mastered the basics.
On the bridge, T'Pol secretly downloads Defiant's schematics from the science station. After arriving on the bridge with Mayweather and a MACO, however, Archer not only orders that he be put in contact with Fleet Admiral Gardner, but also directs the MACO to escort T'Pol to transporter room two. Just before she leaves, Archer makes it clear to T'Pol that she is no longer needed nor wanted aboard the ship. Gardner appears on the viewscreen and is furiously astounded that Archer has had the gall to demand Starfleet's "unconditional surrender." Explaining that Admiral Black is currently unavailable, Archer exchanges threats with Gardner over the consequences of whether the Defiant is permitted access to Earth, though the Fleet Admiral is far more serious in his demeanor. He warns Archer that the Defiant will be fired upon if it continues to approach Earth, then cuts the channel.
While walking through a corridor of the Defiant, Phlox is signaled by an intercom with a request for his immediate presence aboard the Avenger, apparently due to an unspecified medical emergency. Soon after arriving there, however, he finds that neither T'Pol nor Soval are injured.
On the walkway above Avenger's launch bay, the Vulcans attempt to convince Phlox to join their mutinous crusade. The doctor is initially astonished that they want him to sabotage the Defiant. Although he continues to dispute their ideas, Phlox starts to become convinced to join them, after the Vulcans tempt him by imagining what the Emperor might grant him in return for saving his life from Archer, such as an unlimited number of concubines. Ultimately, Phlox justifies the Vulcans' plan to himself.
T'Pol later hurries through a corridor aboard Avenger but is confronted by Hoshi Sato and a MACO, who have phase weapons poised at the ready. Sato demands to know where the downloaded schematics are, but T'Pol feigns mere confusion. Despite Sato trying to take T'Pol back into custody, the Vulcan repeatedly attacks the MACO and a fight ensues between T'Pol and Sato, the women exchanging catty insults. T'Pol eventually knocks Sato to the deck, but her attempted escape is thwarted by the MACO, who stuns T'Pol with his own particle rifle. Standing back up, Sato orders the MACO to bring T'Pol with them.
Meanwhile, Phlox sneaks into a Jefferies tube aboard the Defiant and Soval oversees the securing of the Avenger's bridge, an Andorian male and an Orion female manning the helm and tactical stations, respectively.
Having learned of T'Pol's most recent mutiny against him, Archer talks with her in the briefing room, having obtained her copy of downloaded Defiant schematics, while Sato sits nearby. An uncooperative T'Pol contends that an alliance like the Federation is inevitable in their own universe and that Humanity will eventually pay for its arrogance.
Phlox begins to sabotage the Defiant from inside an access tunnel and is, at first, assisted with vocal commands from Soval, who remains on Avenger's bridge. Aboard the Defiant, the sabotage results in a power drain developing, which Tucker decides to personally investigate. Aided by the gradual loss of the Defiant's total power, Avenger launches an incessant offensive against the Defiant, aboard which Tucker finds and battles Phlox. After managing to floor the saboteur, Tucker re-energizes the Defiant, restoring the craft's shields and weapon systems. The Defiant retaliates against Avenger, which Archer purposefully destroys.
Later lying down on their bunk while drenched in sweat, Archer tells Sato to delete the historical database on the following morning. As Sato hands him a glass from the floor and takes one for herself, Archer fears that anyone else might become inspired by the Federation. The couple toast their drinks to his plan before Sato changes the subject of discussion, wondering if he thinks Starfleet's commanders will support him. Archer believes they are consistently loyal to whomever holds the title of Emperor and, upon considering the start of his own reign, he pours a celebratory drink into his throat while holding his glass in the air. He continues to plot his reign but his words become thready and he collapses to the floor, clutching his chest in agony. After rushing to the room's door, Sato opens it for Mayweather, who she passionately kisses while a pained Archer watches, realizing she has betrayed him before he loses consciousness.
The Defiant orbits Earth as Sato enters the bridge, accompanied by Mayweather and a MACO. At her instruction, Fleet Admiral Gardner appears on the viewscreen. Sato threatens the admiral that the Defiant will attack Earth if Starfleet does not immediately surrender. She identifies herself, to a perplexed Gardner, as "Empress Sato" and advises him to await her commands.
"It may take centuries, but one day Humanity will pay for its arrogance."
- - T'Pol, referring to the eventual events of "Crossover"
"These people had some strange ideas about uniforms."
- - Hoshi Sato, on the crew of the Defiant's Starfleet uniforms
"They're never going to give you this ship. You know that. They'll tear it apart, try to learn its secrets. If you're lucky, you'll end up commanding a moon shuttle. Don't you see what the Admiral's planning? He's going to present this ship to the Emperor himself. He'll take all the credit, and you'll end up a historical footnote."
- - Jonathan Archer's subconscious, about Admiral Black's plans for the USS Defiant
"Perhaps it was a pet, owned by the original crew."
"Unless one of them owned a velociraptor, I find it extremely unlikely."
- - Malcolm Reed and Phlox, referring to Kelby's reptilian killer
"We cannot put down this rebellion so long as our forces are commanded by dishonorable men. Before we can defeat the rebels, we must defeat them. That ship out there is the key to our victory. With the Defiant on our side, there will be nothing to stop us."
- - Jonathan Archer
"This is the starship Defiant. If you don't surrender immediately, we'll begin targeting your cities. Please respond."
"Where's Archer?! And who the hell are you?!!"
"You are speaking with Empress Sato. Prepare to receive instructions."
- - Hoshi Sato and Admiral Gardner
"Great men are not 'peacemakers'. Great men are conquerors!"
- - Jonathan Archer
"I can't find a mention of it anywhere."
"A mention of what?"
"The Empire. As far as I can tell, it doesn't exist in the other universe."
"A lot of the names are the same, but their history has been rewritten. Instead of building an empire, Earth became part of an interspecies alliance."
"The United Federation of Planets?"
"More like a Federation of fools."
- - Jonathan Archer and Hoshi Sato, remarking on the creation of the United Federation of Planets in our universe
"You're confusing our universe with someone else's!"
- - Jonathan Archer
- This episode is both a prequel to TOS: "Mirror, Mirror" and a sequel to TOS: "The Tholian Web".
- This episode (in common with the first installment of its two-parter) differs from the mirror universe episodes of TOS and DS9, in which characters from the regular universe travel to the parallel universe (and vice versa). The two-part "In a Mirror, Darkly" story of ENT takes place entirely in the mirror universe, with no crossover of any regular characters (although, in this episode, information about the characters does crossover and, as in the story's first part, the Constitution-class Defiant is established as having crossed over).
- This episode contains two main elements from TOS: "The Tholian Web": the starship Defiant (whose fate is made known in this episode) and Tholian technology (such as their web and ships).
- The title of this episode comes from a passage in the Bible (1 Corinthians 13:12 from the American Standard Version): "For now we see in a mirror, darkly; but then face to face: now I know in part; but then shall I know fully even as also I was fully known." The same verse (in the King James Bible, the relevant text reads "For now we see through a glass, darkly") is quoted by Captain Picard in Star Trek Nemesis. For this episode's two-parter, the title went through many permutations but writer Mike Sussman ultimately decided that he liked evoking the "mirror" of the quote. (ENT Season 4 DVD audio commentary)
- This episode reuses the same alternate credits that were first revealed in the previous installment.
- The notion of making the "In a Mirror, Darkly" story a two-parter was originally conceived of as a way to afford the construction of more Constitution-class sets, for the Defiant, than had ever been shown in any official Star Trek production since the original series. Mike Sussman's original idea for the story included only one part, however, as he was initially unsure what the second part would be. (Inside the Mirror Episodes, ENT Season 4 DVD special features)
- The answer to the question of who would write this episode changed during the episode's early stages. Even while writing the previous installment, Mike Sussman didn't know that he would be writing this follow-up episode. (Inside the Mirror Episodes, ENT Season 4 DVD special features) In fact, responsibility of writing this episode's teleplay changed from Manny Coto to Sussman, after the latter completed the story's first part. Sussman recounts, "I'd written Part 1 and Manny was in line to write Part 2 and did, in fact, write the story for Part 2 – that's worth pointing out. And he came into my office to, you know, [say] 'Very nice job with Part 1. It's too bad you can't write Part 2.' And I was like, 'Well, you know what? I'm willing to give it a shot if you let me.' And he seemed more than happy to let me do that." Immediately thereafter, Sussman scrambled to write the teleplay for this episode. He was still writing this episode while the preceding episode was in production; the experience of writing two episodes back-to-back was new to Sussman and he therefore wanted to devote as much time to crafting the episodes as he possibly could, even if working on this episode did mean missing out on some of the production of the previous installment. (ENT Season 4 DVD audio commentary)
- Although Mike Sussman initially expected Phlox would help T'Pol begin the mutiny against Archer in this episode, the writer ultimately decided to make Soval act as T'Pol's original collaborator. Of his thought processes concerning this change, Sussman says, "Initially, my idea – going into the script – was... I really thought that it would be T'Pol and Phlox, as the resident aliens on Enterprise, who could sort of turn the tables on Archer and get the better of him. But I realized Phlox had become such a wonderful 'bad guy' that you never quite... You couldn't buy Phlox having a conscience. He just seemed to be devoid of one. So I needed another character for T'Pol to work with and to sort of bond with. And Soval seemed a natural choice." The character of Soval was duly added into the story and was appropriately made more of an underdog character than his regular-universe counterpart. (ENT Season 4 DVD audio commentary)
- Although Mike Sussman was wary of the cliché of characters from the mirror universe sporting a goatee, the writer suggested giving Soval a goatee in this episode. (ENT Season 4 DVD audio commentary)
- The concept of a knife-fight between Hoshi Sato and T'Pol was originally suggested by Manny Coto, although its particular placement in the story was decided upon by Mike Sussman. The scripted version of the fight did not include the catty exchange of remarks that is present in the scene's final version. (ENT Season 4 DVD audio commentary)
- The script reveals that the scene in which Doctor Phlox learns about a medical emergency aboard the Avenger was originally set in the Denobulan's quarters aboard the Defiant, not in a corridor. This minor change was made to save time and money. (Information provided by Mike Sussman)
- Phlox's speech comparing Shakespeare in the two universes was influenced by a passage in the non-canon novel Dark Mirror, which Mike Sussman read before writing the script. Additionally, author Diane Duane's decision to make the mirror version of Reginald Barclay the personal guard of Mirror Picard inspired Sussman to make Mayweather the chief bodyguard for Archer. (Information provided by Mike Sussman) Although Mayweather continues to serve as Archer's personal guard in this episode, his promotion to that position is depicted in the story's first installment, "In a Mirror, Darkly".
- Rather than continue to wear the bulky EV suits they came aboard in, Archer, Reed, T'Pol, Tucker, and Mayweather raid the closets of the Defiant and don TOS-style uniforms. According to Mike Sussman, the away team beamed aboard in the EV suits mainly so that there would be a reasonably believable explanation for why the crew would wear them. (Inside the Mirror Episodes, ENT Season 4 DVD special features)
- Mike Sussman tried to make Hoshi Sato repeatedly seem like a bartender to Archer, pouring him drinks, as the writer thought that this would make Archer's denouement less obvious, prior to him meeting his eventual fate in the episode's penultimate scene. (ENT Season 4 DVD audio commentary)
- Originally, scenes set in the Defiant's briefing room outnumbered the few scenes that were set on the starship's bridge. After this was pointed out to Mike Sussman – looking at the beatsheet, the outline for the episode – he realized the audience would likely want to see more of the bridge. Due to not only this but also because the bridge set cost a vast sum of money to build, Sussman decided to change the setting of at least two scenes from the briefing room to the bridge, even though those scenes were of a talkative nature more suited to the briefing room. One of these scenes was the one in which Archer and his officers discuss Kelby's reptilian killer, immediately after Kelby's death. (ENT Season 4 DVD audio commentary)
- The climactic fight between Phlox and Tucker was originally scripted to be shot in the emergency manual monitor, a room overlooking main engineering. Unfortunately, the expense of building this set (and the optical effects showing a computer-generated Engineering through the window) necessitated the action be moved to the access tunnels. (Information provided by Mike Sussman)
- The blue-skinned slave worker was not named in the script of this episode. Early in the episode's development, it was discussed that the alien slave would likely be Human-looking with subtle prosthetics. However, Mike Sussman was ultimately very pleased with Michael Westmore's final design for the alien. (ENT Season 4 DVD audio commentary)
- Prior to this episode, the writers had spent much time trying to find some means of including the Gorn into the series without violating continuity. This episode's break from the regular universe allowed for the Gorn's inclusion. (ENT Season 4 DVD audio commentary)
- During Archer's first contact with Slar, the Gorn "speaks" in growls and snarls that are somehow converted into a male, English computer voice (likely via a universal translator hidden in a communicator that Slar holds, during the scene). This complication in communication was intentional, on Mike Sussman's part. (ENT Season 4 DVD audio commentary)
- The method Archer later uses to down Slar – utilizing the ship's gravity plating – was only added to the episode's script after Mike Sussman had spent about two years trying to write such a setup into scripts of other episodes, although it had kept being cut as it hadn't quite fitted into the other stories. Sussman was at a loss for how Archer would defeat the Gorn when the writer realized that, on this occasion, the setup would work. (ENT Season 4 DVD audio commentary)
- In the story's original version, the Defiant simply rendezvoused with Avenger. Mike Sussman added the scene involving the hostile rebel ships, however, as he had an enthusiasm for starship battle scenes in Star Trek. (ENT Season 4 DVD audio commentary)
- The scene wherein T'Pol and Phlox have a conversation in the officers' lounge of the Defiant was not included in the episode's original outline. However, Mike Sussman decided that he wanted a quiet moment between the two battle scenes of Archer defeating the Gorn, and the Defiant rescuing Avenger from the rebel ships. Sussman usually enjoyed writing scenes that featured the regular-universe T'Pol and Phlox so it seemed natural for him to write a scene that featured their mirror counterparts and he was interested to see what the scene would be like. In the scene's final version, the pair of characters are sitting at a table on which are two plates of cubed food that, in the original series, is typically produced by food synthesizers. This food was referred to in the script of this episode. (ENT Season 4 DVD audio commentary)
- In the writing of this episode, Mike Sussman wanted to include a hint of some of the mirror universe episodes that had been done on Star Trek: Deep Space Nine. He consequently added T'Pol's vow that Humanity will eventually pay for its arrogance, a line of dialogue that Sussman intended as a subtle reference to the future defeat of the Terran Empire, which is first established (as having happened) in DS9: "Crossover", the first of the series' mirror universe episodes. (ENT Season 4 DVD audio commentary)
- Discussion between Mike Sussman and Manny Coto about revisiting the mirror universe in a potential fifth season of Star Trek: Enterprise influenced the fate of Major Reed in this episode; Sussman decided to leave open the possibility that the Mirror Reed survived being bombed, just in case the writers wanted to bring the character back in the following season. (ENT Season 4 DVD audio commentary)
- Archer's fate is similarly left open. In the episode's audio commentary, Mike Sussman comments that, although Sato probably poisoned Archer, she may have possibly just drugged him.
- Archer's defeat by Sato and Mayweather was thought up by Manny Coto. Mike Sussman recounts, "From the beginning, Manny had suggested that Hoshi would end up on top, at the end. Hoshi and Mayweather. And it would sort of be the revenge of the day players, or the revenge of the little people. And in the end, everyone else is either dead or dying and they end up in charge." (ENT Season 4 DVD audio commentary)
- Sato's communication with Admiral Gardner at the episode's conclusion was initially to have been a comm call, but production staff other than Mike Sussman changed it to being a viewscreen exchange, which Sussman ultimately preferred. (ENT Season 4 DVD audio commentary)
- Mike Sussman was not particularly proud of a shot that shows Kelby being dragged into an access tube above him, as the writer thought that, realistically, Kelby would have been kicking harder than he does in the shot. To explain away the shot's lack of realism, Sussman devised a theory that Kelby's spinal cord was severed during the attack. (ENT Season 4 DVD audio commentary)
- This episode, like the first part of the episode's two-parter, was originally two or three minutes overlong. (ENT Season 4 DVD audio commentary)
- The trims that were made to the episode included extra footage of Mayweather brutalizing the alien slave worker. (ENT Season 4 DVD audio commentary)
- A shot of Mike Sussman as a deceased officer, lying face up in a corridor, was cut from the episode as well. (ENT Season 4 DVD audio commentary)
- Another edit from the episode was a preface to the scene wherein T'Pol and Phlox are talking in the Defiant's briefing room. Of the removed footage, Mike Sussman says, "This scene initially was longer, where T'Pol goes to one of the food synthesizers, gets out a plate of colored cubes and sits down, and Phlox says, 'Of all the things you could have chosen, that is what you want to eat?!' That little bit got trimmed out." (ENT Season 4 DVD audio commentary)
- Archer's rousing "call to action" speech in Avenger's cargo bay was also trimmed for the final episode but, in this case, the full version is available as a deleted scene in the Season 4 DVD set for Star Trek: Enterprise. The deleted section predominantly features a quote from Julius Caesar's legendary battle cry ("the die is now cast"), allegedly spoken as Caesar crossed the Rubicon at the beginning of another civil war. In the deleted footage, this quote is followed by Archer's audience saluting him before breaking into applause, and Archer telling Mayweather to "shoot the first one who stops applauding". Sussman recalls, "There was a very funny moment where he goes up the ladder, to the top, where Mayweather is and says, 'Shoot the first one who stops applauding.' That was probably a little over the top. And again, it did not survive the brutal editing process. And probably for the better." (ENT Season 4 DVD audio commentary)
Sets, props, and wardrobe
- The green dress uniform Archer wears is the only uniform, shown in this episode, that has rank braids on its sleeves.
- During production, actress Nicole Malgarini – playing a deceased command division lieutenant among the lifeless officers littering the deck, in the scene where Archer hunts the Gorn – became worried about the length of her Starfleet miniskirt uniform, obviously having never seen the original series. Mike Sussman recalls, "It was very funny. She was walking around in her miniskirt, asking, 'Is it supposed to be this short? It's really, really short.' [...] The consensus was, 'Yes, it's supposed to be that short.'" (ENT Season 4 DVD audio commentary) The minidress, which had previously been used for DS9: "Trials and Tribble-ations", was auctioned off in the "40 Years of Star Trek: The Collection" auction in 2006. 
- This episode features the reconstructed Constitution-class bridge set that first appeared in the story's first installment. Photographs show that it was during the production of this episode (rather than in the previous one) that production personnel, including Manny Coto and director Marvin V. Rush, were pictured on the bridge set, sitting in the captain's chair.
- This episode also features many Constitution-class corridor sets, one of which appeared in the previous installment. Almost as much corridor was constructed for this episode as had been built for DS9: "Trials and Tribble-ations". The corridors here had several features that had been omitted from previous reconstructions, including a Jefferies tube (albeit one that was sightly wider than the original set, to allow people wearing spacesuits to climb up it). Although corridor intercoms had been made for "Trials and Tribble-ations", they had subsequently not survived in storage, so they all had to be rebuilt for this episode. (ENT Season 4 DVD text commentary)
- Two distinctly different sets were built to represent the Defiant's access tunnels in this episode: the tunnel where Kelby is killed (and where Archer and his assault team later begin their hunt for the Gorn), and a tunnel where Reed and his three accompanying MACOs are bombed (which also served, slightly redressed, as the access tunnel where Phlox attempts to sabotage the Defiant). (ENT Season 4 DVD text commentary) According to a slightly uncertain Mike Sussman, these sets were actually the access tubes from the regular NX-class Enterprise, redressed to make them appear as if they were from the original series. (ENT Season 4 DVD audio commentary) Styling them in such a way involved the addition of distinctive perforated metal patterns, as well as use of original series colors in pipes of both sets. In homage to original series set decorator John Dwyer, a few of the Defiant's pipes – as with the Enterprise of the original series – were labeled with the initials "GNDN", an in-joke indicating that each labeled component "Goes Nowhere, Does Nothing." (ENT Season 4 DVD text commentary)
- The first access tunnel set was partly constructed on the remains of a set that had been used as the secret Nazi complex in ENT: "Storm Front". In this case, the set featured a back wall that included detailing based on a set that had been built for an original series episode but was never actually shown. (ENT Season 4 DVD text commentary)
- The other tunnel set was mostly made of stock set pieces and its walls were actually vacuformed plastic sheets that had originally been designed for Star Trek V: The Final Frontier. The slight redressing of the set for the scene in which Phlox attempts to sabotage the Defiant featured red relay tubes that had been used as control rods in the Xindi weapon, for the third season ENT episode "Zero Hour". The same tunnel set was later modified for subsequent episodes "Demons" and "Terra Prime", becoming corridors of the Orpheus Mining Complex for that two-parter. (ENT Season 4 DVD text commentary)
- The officers' lounge aboard the Defiant was actually – as had been the case with the Enterprise's version in the original series – a redress of the ship's briefing room set. Food that is present in the same scene was prepared by Star Trek food stylist Dorothy Duder, using exotic fruits (among other things) to make the food look like the colorful "space food" that repeatedly appears in the original series. Another item linking the scene to the original series was the presence of a copy of Spock's three-dimensional chess set. Although a similar chess set had been recreated for the Ten Forward lounge of Star Trek: The Next Generation and was later reused in a recreation of Ten Forward in ENT: "These Are the Voyages...", the chess set seen here was especially made for this episode and was recreated by Paramount's special effects shop using screen captures from a Star Trek DVD. (ENT Season 4 DVD text commentary)
- Despite the fact that both the Defiant of this episode and the Enterprise of the original series are established as being Constitution-class ships, there are a number of differences between the equivalent sets used for the two vessels. Of course, this is not necessarily a continuity error, as the crafts are indeed two different ships. (ENT Season 4 DVD text commentary)
- A straight vertical access tube that, upon beginning their hunt for the Gorn, Archer and his assault team ascend (immediately prior to entering one of the two access tunnels that were built for this episode) was recycled from the earlier Season 4 episode "Cold Station 12", for the title station of that episode. Consequently, the access tube featured ribs and other details that were not included in the area's equivalent from the original series. Metallic wallpaper was applied to the tube's interior, in an effort to make it seem more like the original set. (ENT Season 4 DVD text commentary)
- The captain's quarters in this episode were built on Paramount Stage 18. They are slightly different from Kirk's quarters of the original series, incorporating a different style of room-divider and a slightly thinner desktop viewer. (ENT Season 4 DVD text commentary) In this episode, the grating that divides the area's two rooms consisted of material that was also used in the Defiant's corridor set and was (according to Michael Okuda, as relayed by Tim Gaskill) sourced from the same company that had provided similar gratings for the Enterprise of the original series. (ENT Season 4 DVD text commentary and audio commentary) Also, the desktop viewer of the captain's quarters was rigged with a real computer monitor screen. Although the original prop had been made at a time when all televisions used bulky vacuum tube screens, the recreated prop made use of a flat-screen panel, the likes of which are much more advanced than the screen technology that was available at the time of the original series' production. (ENT Season 4 DVD text commentary)
- The recreated briefing room of this episode was designed by set designer Ahna Packard, using reference photographs and DVD images from the original series. Packard adjusted her design to fit into the available stage space, which was a small area just in front of the set used for the bridge of the NX-class Enterprise that usually featured in ENT. As a result, the briefing room set was slightly smaller than the one used as the Enterprise's briefing room in the original series. The table included in the new set was slightly smaller than the one that had been included in the earlier set. A functional tri-screen was positioned on the table, having originally been built for Admiral Forrest's office in ENT: "Home". The set also included a blue Federation flag prop that had originally been made for Starbase 375 (which appears in four early episodes of DS9's sixth season) and had subsequently been reused to grace Jadzia Dax's coffin (in DS9's Season 6 finale, "Tears of the Prophets"). (ENT Season 4 DVD text commentary) In this episode's audio commentary, Tim Gaskill implies that he believes the large amount of space in the briefing room, compared to the NX-class Enterprise that usually featured in ENT, helps avoid the Defiant seeming retro, by comparison.
- While the exterior of Avenger was a slightly modified digital model that had been used as the Columbia NX-02 in four earlier episodes of ENT (three of which are, like this episode, part of the fourth season of the series), the starship's bridge was a minor redress of the regular NX-class Enterprise's bridge. In this case, the set included a back wall that had originally been used for the bridge of the Intrepid, in the Season 2 ENT episode "The Expanse" (which, incidentally, is also the first episode in which Columbia's exterior appears). (ENT Season 4 DVD text commentary)
Graphics and displays
- A painting of an 18th century British warship, the HMS Defiant, can be seen on one wall of the briefing room aboard the Federation Defiant and was called for in the episode's teleplay. In real life, however, no such sailing vessel ever existed. A fictional Defiant was seen in the 1962 movie Damn The Defiant! (based on the Frank Tilsey novel Mutiny), which may have been the namesake for the Constitution-class ship. It was only after the art department had created the image that Sussman discovered the vessel had not really existed in history. (ENT Season 4 DVD audio commentary) The image was digitally created, using a composite of several different photographs of real ships. Production designer Herman Zimmerman liked the faux painting so much that he had a similar picture created, this time showing the starship Defiant. In the episode, the two images are positioned directly next to each other. (ENT Season 4 DVD text commentary)
- Three pages of historical details are displayed on a desktop viewer in the captain's quarters of the Defiant. Most of the information was provided by Mike Sussman, who was free to detail the future histories of the regular-universe Archer and Sato – which Sussman found was "a lot of fun" to do. (ENT Season 4 DVD audio commentary) The screen display format that incorporates the historical pages was designed by scenic artist James Van Over, who based the displays on screens that had appeared on the original series, including white backgrounds and bright blue borders. (ENT Season 4 DVD text commentary) Ultimately, Sussman was surprised that much of what he'd written was clearly legible in high-definition in the completed episode. (ENT Season 4 DVD audio commentary)
- In production art, this episode confirms James T. Kirk's month, date and year of birth: March 22nd, 2233. In real life, William Shatner celebrates his birthday on March 22nd. 
- A freeze-frame of Archer's bio reveals that he will later become an Admiral and serve as Starfleet Chief of Staff, Ambassador to Andoria, Federation councilman, and Federation President (2184 – 2192). It also says that historian John Gill considered Archer the "greatest explorer of the 22nd Century," and that two planets were named after him, one of them Archer IV, the planet his crew visited in "Strange New World". The original production artwork can be viewed on the Twitter timeline of writer Mike Sussman. 
- Although it did not appear on-screen, the final section of the bio would have revealed that Archer dies in 2245, one day after attending the christening ceremony of the USS Enterprise, the first Federation starship to bear the name. 
- Mike Sussman loved scripting such details as the in-depth Defiant schematic that Reed shows Archer, as the writer expected the diagram would give technically-minded fans something to pore over for probably years into the future. (ENT Season 4 DVD audio commentary) Created by Doug Drexler and James Van Over, the Defiant schematic was actually present on the set, owing to the fact that the viewscreen was rear-projected. This was thanks to video engineers Ben Betts and Eric Roberts, who were also responsible for operating the projectors that provided the slowly moving graphics on the bridge's upper screens. (ENT Season 4 DVD text commentary)
- For the scene in which T'Pol downloads Defiant's schematics from the vessel's computer, the information is shown on one of the science station's rear light panels as it is being downloaded. Mike Sussman requested this of the art department, as he wanted the audience to see the information but not on one of the big overhead monitors, where the data would be less discreet. (ENT Season 4 DVD audio commentary)
Modernizing the Gorn
- Following the Tholians of the previous installment, this is the second episode in a row to feature the return of an alien not seen since the original or animated series – in this case, the Gorn, which first appeared in TOS: "Arena".
- Initially, the production crew were perplexed as to how they would create the Gorn required for this episode. Michael Westmore explains, "With the Gorn... in the beginning, they didn't know what direction we were gonna go in. Are you going to put a man in a suit? And if we do, what modifications are you going to make, so it doesn't look like the original one [...] which was very bulky and very hard for the actor to move around in? We played around with the idea, and we all came... Basically, all of us came to the same conclusion. If we want to do something that's new and that's still à la Gorn, it's going to have to be an optical – not a man in a suit." (Inside the Mirror Episodes, ENT Season 4 DVD special features) This method of creating the modernized Gorn would allow it to have much more freedom of movement than had been possible with its predecessor in the original series. (ENT Season 4 DVD text commentary)
- Subsequently, Earl Ellis – a sculptor in Michael Westmore's makeup department – created an eighteen-inch clay maquette of a potential Gorn design that was further developed with input from producers Manny Coto, Rick Berman and Brannon Braga. Westmore echoes their advice, saying, "'Well, maybe it should be a little bit more of this. The shoulders should be a little bigger. Maybe the chest should be a little bigger. It looks too much like a Human. Can you extend the torso?'" As the final maquette was a very useful starting point for the creation of a digital model, the maquette was given to visual effects producer Dan Curry who, in turn, gave it to digital effects supervisor John Teska at Eden FX. Teska was then able to transform the design into a fully animatable computer-generated Gorn. (Inside the Mirror Episodes, ENT Season 4 DVD special features)
- Meanwhile, footage of stunt coordinator Vince Deadrick, Jr., playing the Gorn – dressed in a fitted black leotard outfit that had white grid marks on – and acting alongside Scott Bakula, was filmed. (Inside the Mirror Episodes, ENT Season 4 DVD special features) The same shots were then repeated, with Bakula alone reenacting Archer's movements in the footage. (ENT Season 4 DVD audio commentary) Finally, the computer-generated Gorn was added into the shots, replacing Deadrick's movements. (Inside the Mirror Episodes, ENT Season 4 DVD special features)
- For close-up shots of the Gorn's alien hands, a pair of Gorn gloves were especially designed by Michael Westmore's makeup effects department. (Inside the Mirror Episodes, ENT Season 4 DVD special features)
Cast and characters
- In this episode, Majel Barrett-Roddenberry reprises her role of a ship's computer voice (in this case, voicing the Defiant's computer). Her inclusion here meant she had been credited as a performer in all six televised Star Trek series, and all five live-action versions, produced during her lifetime. As well as playing several characters (such as Number One, Nurse Chapel, and Lwaxana Troi), she also provided the voice for the computers aboard USS Enterprise, USS Enterprise-D, USS Defiant (NX-74205), various runabouts, and the USS Voyager. This episode was the penultimate official Star Trek production that she worked on, later voicing the ship's computer aboard the USS Enterprise of the alternate reality, in 2009's Star Trek.
- Bobby Clark, who played the Gorn in the Star Trek: The Original Series original series episode "Arena", as well as one of Pavel Chekov's guards in "Mirror, Mirror" was on the set during the filming of Archer's fight with Slar. Clark was a guest of Star Trek: Enterprise stunt coordinator Vince Deadrick, Jr., who has his own personal connection to Star Trek; he is the son of Vince Deadrick, an actor and stuntman who appeared in numerous episodes of the original series. (Information provided by Mike Sussman)
- Similarly, on the day after filming of the scene wherein Archer and Hoshi Sato sit up from bed in the darkened captain's quarters, executive producer Manny Coto had a visit from special guest Barbara Luna, who had appeared in "Mirror, Mirror" as Marlena Moreau – the original "captain's woman." Luna stopped by to say a quick "hello" and gave Coto an autographed copy of the Terran Empire symbol. She later visited the set of the recreated Constitution-class captain's quarters to give the set her seal of approval. (ENT Season 4 DVD text commentary)
- Despite one of his cameo shots being cut, Mike Sussman still appears in this episode – in his only on-screen role to date – as another dead officer, a redshirt littering the deck during Archer's hunt for the Gorn. Only the writer's lower body appears, however. (ENT Season 4 DVD audio commentary)
- This episode is both the fourth of five Star Trek episodes that Marvin V. Rush directed, in total, and the first Star Trek episode that he directed in eight years. The previous episode he directed was the 1997 Star Trek: Voyager episode "Favorite Son". Rush normally served as the Director of Photography on the live-action Star Trek spin-off series. For Star Trek: Enterprise, he not only directed this episode but also the later Season 4 episode "Terra Prime". While Rush prepped and directed this episode, camera operator Doug Knapp was promoted to serving as the Director of Photography. (ENT Season 4 DVD text commentary)
- When deciding upon the look of the Defiant's Constitution-class bridge, Mike Sussman provided Rush with a videotape of The Tholian Web (featuring the Defiant and Enterprise) and Sussman's own DVD copy of TOS: "The Doomsday Machine" (featuring the wrecked USS Constellation as well as the Enterprise). Rush particularly enjoyed working on the final version of the Defiant bridge set. (ENT Season 4 DVD audio commentary)
- The scene wherein Archer and Sato have a bedside discussion in the darkened captain's quarters was filmed by Rush in one long, continuous take. Capturing the take took many tries, however, as – according to a slightly uncertain Mike Sussman – Scott Bakula was intentionally flubbing his lines. Bakula and Linda Park also experimented with different ways of doing the scene, varying the speed of their performances. (ENT Season 4 DVD audio commentary)
- The exchange of catty remarks between Hoshi Sato and T'Pol in their knife fight scene was suggested by Rush when, on the morning of filming the scene, he called Mike Sussman from the set. Sussman and Rush then worked on coming up with the bitchy dialogue, with one of the lines being thought up by Rick Berman. (ENT Season 4 DVD audio commentary)
- The scene wherein Archer makes a lengthy spiel to a group of gathered officers was filmed on Wednesday, 2 February, 2005. During production on the scene, UPN declared that Star Trek: Enterprise was being canceled at the end of the season. As soon as the news was officially made, the production office discreetly notified the series' department heads. However, word of the cancellation quickly spread throughout the series' cast and crew. Even though everyone involved in the making of the series had anticipated such an announcement, they were saddened to learn of the news. (ENT Season 4 DVD text commentary)
- Although the cast and crew were exhausted after completing this episode, they restlessly continued – as they were required to do – with the remaining three episodes of the series. (ENT Season 4 DVD text commentary)
- Although the Starfleet character of Gardner is repeatedly mentioned throughout Star Trek: Enterprise, this is the only episode to feature his likeness as he himself does not appear in the series, other than the presence of his mirror universe counterpart in this episode.
- This is the only episode of ENT where no scenes take place aboard or near a starship Enterprise (from either the regular or mirror universe).
- This is the second episode in a row to feature the destruction of an NX-class ship; whereas Avenger is destroyed by the Defiant in this episode, the NX-class Enterprise was obliterated by the Tholians in the previous installment.
- Even though the Enterprise of the original series was neither equipped with aft torpedoes nor aft phasers, the Defiant uses them to free itself from the Tholian drydock near the start of this episode. This can be explained by the fact that, although both ships are of the same class, they are nevertheless individual vessels. In the episode's audio commentary, Mike Sussman remarks, "You can blame the writer for this." He goes on to explain, "It always seemed to me that – if Archer's ship had these aft weapons – that certainly, you know, a ship a hundred years later would have that kind of technology, as well."
- This episode is the only one in which a character other than Kirk is shown wearing the "green wrap-around shirt" that he originated.
- The presence of a bottled green liquid in the captain's quarters of the Defiant – during the scene in which Archer shows off his newly-acquired captain's dress uniform to Hoshi Sato – is an homage to a drunken Montgomery Scott describing, in TOS: "By Any Other Name", a similar (if not identical) drink by saying no other comment than it is green. (ENT Season 4 DVD audio commentary) This line was also referenced in TNG: "Relics".
- As the Defiant disappeared from the primary universe after Kirk, McCoy, Scott, and Uhura's crossover, the Defiant's computers should have some mention of the Terran Empire. Since Archer can't find any mention of it, either such information was not included in the ship's databanks or Archer simply didn't look hard enough. Possible reasons for the information not to have been included are that Kirk's report on his encounter with the mirror universe was perhaps classified or that the Defiant's computers hadn't been updated to include such information, prior to the vessel's disappearance.
- The Defiant's unique rank insignia reappears here, having first appeared in the previous episode. The use of the insignia continues the original series' tradition of most but not all Federation starships having their own insignia, on crew uniforms.
- When T'Pol summons another slave prisoner to the briefing room, the intercom sound effect from Star Trek: The Next Generation is used.
- In a "tip-of-the-hat" to The Original Series, T'Pol's scenes at the library computer station on the Defiant bridge were shot at the same angles as Spock's were.
- This episode marks the first time that the classic red alert klaxon, which was used throughout all of the classic Star Trek series and throughout Star Trek: The Next Generation, is used since DS9: "Waltz", where it was used aboard the USS Honshu.
- In TOS, it is never shown where nor how the Jefferies tubes end up. It was first established here that they lead to wider, horizontal access tunnels, through which crew members can walk (slightly crouched).
- In common with many officers in the original series, Reed is wearing a red security division Starfleet uniform of the 23rd century upon meeting an horrific fate (in this case, being badly injured by Slar's bomb).
- Although this episode establishes that the scene wherein Archer defeats the Gorn takes place in a corridor of the primary hull and that he was in the ship's lower hull immediately beforehand, he climbs down through the ceiling to enter the corridor, instead of climbing up through the floor (as he should have done). This was because there was insufficient time and money to cut a hole in the floor of the set.
- In the scene that features Phlox and T'Pol having a discussion in the officers' lounge of the Defiant, Phlox drinks from a cup containing a blue liquid. In the episode's audio commentary, Tim Gaskill supposes that the drink is Romulan ale, which was first referenced in Star Trek II: The Wrath of Khan.
- The concept of Phlox being tempted by the promise of unlimited concubines is due to the fact that, in other episodes of ENT, Denobulans are established as having many wives.
- Amid his teasing of Archer after Admiral Black's tour, the hallucinatory manifestation of the regular-universe Archer tells the Mirror Archer that, if he's lucky, he will end up commanding a moon shuttle. This refers to a statement made by Doctor Leonard McCoy in TOS: "The Corbomite Maneuver" (McCoy's first appearance). In that episode, Kirk berates McCoy for not alerting Kirk to the ship's red alert status during a physical, and McCoy then quips, "What am I, a doctor or a moon shuttle conductor?"
- As Mike Sussman notes in this episode's audio commentary, the Defiant schematic is more detailed than any Constitution-class diagram from the original series and the method of downing Slar – using the ship's gravity plating – was "something we haven't quite seen on Star Trek before."
- Whereas Archer kills Slar in this episode, Kirk allows the Gorn in "Arena" to live.
- Like Mirror Spock in "Mirror, Mirror", Mirror Soval sports a goatee in this episode.
- T'Pol's role in this episode echoes Mirror Spock's ultimate decision in "Mirror, Mirror", as both Vulcan characters seek to put an end to the evil of the Terran Empire.
- When Phlox receives the phony "medical emergency" call from the Avenger, he never presses the Defiant's intercom button. Rather, his finger merely touches the right of the intercom grille, and the action is accompanied by unique "on" and "off" sound effects.
- Though Archer order the Defiant's database on the Federation erased the Empress Sato seems to have kept the database intact as knowledge of the Federation is known to the Terran Emperor in the 23rd century and Captain's of Imperial Starships though in redacted form.
- This is the second of only three occurrences of one series' credit style appearing over the sets of another, specifically the white ENT style over reconstructed sets of TOS. The first is in TNG: "Birthright, Part I" and the third in ENT: "These Are the Voyages...". The USS Enterprise appears during the credit sequence of DS9: "Trials and Tribble-ations", without a credit overlay.
- The two-part episode proved to be one of the most popular installments of Enterprise. David Bianculli, the television critic for The New York Daily News, called them "the best hours of Enterprise yet." He wrote, "The biggest treat of this episode, though, is its ability to surprise - and to do so with not only a sense of Trek history, but with a sense of humor." Bianculli added that "by taking a walk on the wild side, Enterprise is being very good by letting its characters be very bad." He rated the episode three-and-a-half out of four stars, and said that it was so much fun that "had they adopted this attitude from the start, Enterprise probably would still be flying missions next season."
- In August 2016, Star Trek fans at the 50th anniversary convention in Las Vegas chose the two-parter as one of the "Ten Best Star Trek Episodes" of all time, out of more than seven-hundred live-action episodes produced as of that date. 
- Wired named the two-part installment as one of twelve "all-time best Star Trek episodes." 
- Newsweek magazine listed the two-hour episode first on its list of the "Top 10" Enterprise episodes. (Newsweek: Star Trek - 50 Years on the Enterprise, January/February 2016, p. 82).
- The readers of Star Trek Magazine selected the two-parter as the best episode of Star Trek: Enterprise in their 40th anniversary reader poll ("Who's on Top?," Issue No. 124, 17 November 2005).
- Cinefantastique magazine listed the two-hour episode at #4 on its list of the top ten television episodes of 2005. ("TV: Best of 2005," Cinefantastique 2005 Yearbook Issue, November 30, 2005, p.8).
- "Everything that was set up in the classic 'Mirror, Mirror' is here and writer Mike Sussman juggles them all expertly," writes IGN.com, awarding the installment five out of five stars. “The actors are obviously having more fun than they've ever had before playing these alternate versions of their regular characters which frankly, have more depth to them than we've seen in the past three-and-a-half years of the series... ['In a Mirror, Darkly'] may be a gimmick episode, but it's a gimmick that works nearly flawlessly and shouldn't be missed.” 
- According to Michael and Denise Okuda's text commentary for this episode, fan reaction was overwhelmingly positive and proved that "Enterprise fans still love the original Star Trek."
- Marvin V. Rush's subsequent assignment of directing "Terra Prime" was as a direct result of the rest of ENT's production staff being impressed by his directorial work on this episode. (ENT Season 4 DVD audio commentary)
- Following the success of the two-part episode, Sussman contributed the story for a sequel novella, "Age of the Empress," published as part of the first in a series of Mirror Universe anthology trade paperbacks. (Mack, David, et al. Glass Empires - Star Trek: Mirror Universe #1. Pocket Books, 2007).
- The guidebook Star Trek 101 by Terry J. Erdmann and Paula M. Block, lists the two-parter as one of the "Ten Essential Episodes" from Star Trek: Enterprise (p. 262).
- Scott Bakula described the two-parter as a favorite episode of his in an interview with SyFy Wire.
- Linda Park, who had a substantial role in the two-parter as the self-proclaimed Empress Sato, has said: "I think it’s well known that those are my favorite episodes." 
- As part of the ENT Season 4 DVD.
- As part of the Star Trek: Fan Collective - Alternate Realities collection.
Links and references
- Scott Bakula as Jonathan Archer
- John Billingsley as Phlox
- Jolene Blalock as T'Pol
- Dominic Keating as Malcolm Reed
- Anthony Montgomery as Travis Mayweather
- Linda Park as Hoshi Sato
- Connor Trinneer as Charles "Trip" Tucker III
- Gary Graham as Soval
- Gregory Itzin as Black
- John Mahon as Gardner
- Derek Magyar as Kelby
- Pat Healy as Alien Slave
- Devon Abner as the Avenger captain
- David Keith Anderson as Slar (CGI close-ups)
- Jef Ayres
- Scott Bakula as Jonathan Archer
- Solomon Burke, Jr.
- Kevin Derr as Kelly
- Duncan K. Fraser
- Glen Hambly as Avenger Andorian helmsman
- Michael Hugghins as B. Scott
- Yoshio Iizuka as V. Brown
- John Jurgens
- Larry Krask as Defiant sciences lieutenant 
- Matt Lavine as Defiant operations crewman 
- Andrea Lockhart as Avenger Orion crewmember
- Andrew MacBeth as E. Hamboyan
- Nicole Malgarini as Defiant command lieutenant
- Kassandra Nelson as Avenger crewwoman 
- Danny Ogden as Avenger crewman 
- Linda Park as Hoshi Sato
- Pablo Soriano
- Cecelia Specht as Avenger crewwoman 
- Justin Sundquist as MACO
- Mike Sussman as Defiant operations crewman
- Chris Torres as B. Moreno
- James Ward as Defiant sciences officer
- Unknown performers as Enterprise Tellarite crewman
- Shawn Crowder as stunt double for Connor Trinneer
- Vince Deadrick, Jr. as
- Diana Lee Inosanto as stunt double for Linda Park
- Clark Tucker as stunt double for Dominic Keating
- Boni Yanagisawa as stunt double for Jolene Blalock
access tube; "all hands"; Andorian; Andorian battle cruiser (unnamed); Archer, Henry; Avenger, ISS; battle stations; career; concubine; conqueror; consort; Constitution-class; councilman; coupler; Defiant, HMS; Defiant, USS; D'kyr-type (unnamed); docking clamps; empress; engineering deck; flush; footnote; g; gesture; Gorn; honorary; inciting the rebels; interplanetary transport; kiss; leader; meter; Military Assault Command Operations; master systems display; microfracture; Orion; peacemaker; photon torpedo; phaser; Plan B; plasma regulator; power grid; primary EPS relay; radius; reaction chamber; rebel; reptilian; revolutionary; saliva; senior officer; Shakespeare, William; Shakespeare, William (mirror); Shuttlepod 1; slave; slavemaster; steamship; subhuman species; Tellarite; Tellarite cruiser (unnamed); Tholian; Tholian ship (unnamed); thruster; unconditional surrender; velociraptor; Vulcan; Vulcan; warship; worker
Historical Archive: Starfleet references
Alpha Centauri; Archon; Battle of Cheron; Beta III; Burke, John; C-111 system; Cochrane, Zefram; Constitution of the United Federation of Planets; Earth-Romulan War; Eminiar VII; Enterprise NX-01; Federation Council; Ficus sector; Iowa; Kirk, James T.; Klingon Empire; Paris; Green, Phillip; President of the United Federation of Planets; Mariposa, SS; Romulan Star Empire; Royal Academy; San Francisco; Sherman's Planet; Starfleet Charter; Valiant, SS; Valiant, USS; World War III
Jonathan Archer bio references
61 Ursae Majoris; Andoria; Andorian Imperial Guard; Archer IV; Archer, Henry; Archer, Sally; Archer's Planet; Chief of Staff; councilman; Federation Citation of Honor; Gamma Trianguli sector; Gill, John; Shran, Thy'lek; Medal of Valor; New York; North America; Preantares Ribbon of Commendation; Star Cross; Warp five engine
Hoshi Sato bio references
Deleted bio references
- "In a Mirror, Darkly, Part II" at StarTrek.com, the official Star Trek website
- "In a Mirror, Darkly" at Memory Beta, the wiki for licensed Star Trek works
- "In a Mirror, Darkly" at Wikipedia
|Mirror universe-related episodes|
|ENT: "In a Mirror, Darkly" • "In a Mirror, Darkly, Part II"|
|DIS: "Into the Forest I Go" • "Despite Yourself" • "The Wolf Inside" • "Vaulting Ambition" • "What's Past Is Prologue" • "Terra Firma, Part 1" • "Terra Firma, Part 2"|
|TOS: "Mirror, Mirror" • "The Tholian Web"|
|DS9: "Crossover" • "Through the Looking Glass" • "Shattered Mirror" • "Resurrection" • "The Emperor's New Cloak"|
"In a Mirror, Darkly"
|Star Trek: Enterprise
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