Sylvia Tilly posing as Captain "Killy".
Discovery finds itself in the Mirror Universe, and they have to find the way home without revealing who they really are. Tyler undergoes a crisis when Culber discovers evidence that he's not who he thinks he is.
Tropes:
- Agony Beam: The agony booth is a standard fixture of Terran brigs. Lorca unfortunately has to spend his time in one, since that's how Terrans treat their prisoners.
- And There Was Much Rejoicing: The Shenzhou's bridge crew breaks into applause when they see that Burnham has killed Mirror Connor, who by his own admission was never as popular as Burnham.
- Anyone Can Die: Tyler snaps Culber's neck when Culber tries to prevent him from going on the mission with Burnham and Lorca, since his tests have him convinced that Tyler is not who he seems.
- Bad "Bad Acting": Tilly's first attempt to pose as her mirror self barely works (and requires a quick assist from Lorca). The second time, she dives right into character.
- Be Careful What You Wish For:
- Tilly wanted to be a starship captain. Now she gets to be an evil Terran starship captain. Naturally, she's not thrilled.
- In a similar vein, Burnham was grateful when Georgiou planned to help her get her own command. Now she also gets to be an evil Terran captain— of the mirror version of the ship that she previously served on. As if that weren't bad enough, one of her first acts is killing the mirror counterpart of the deceased Ensign Connor when he attempts a Klingon Promotion.
- Beneath the Mask: Everyone in the Terran Empire is putting on a fierce front to mask fear, at least according to Burnham.Burnham: Terran strength is born out of pure necessity. Because they live in constant fear, always looking for the next knife aimed at their back. Their strength is painted rust. It's a façade.
- Brief Accent Imitation: Lorca does an impression of a Scottish accent when Burnham tells him not to give away his true identity.
- Body Horror: Culber's description of the surgical alteration done to Tyler/Voq is disturbing. What drops it to
Fridge Horror levels is that while Culber identified significant scarring around the organs that hadn't been detected previously, there was apparently nothing odd about the organs themselves... suggesting that they're the real Tyler's organs. - Bury Your Gays: Culber gets his neck snapped when he gets too close to the truth about Tyler. In After Trek, Executive Producer Aaron Harberts claims that they are very much aware of the trope and try to avoid the bad parts of it.
- Call-Back: The Trigger Phrase that L'Rell uses on Tyler/Voq is the prayer that Voq and the dying T'Kuvma recited.
- Cassandra Truth: Stamets briefly becomes lucid (signified by his eyes briefly returning to normal) and tells Culber "The enemy is here!" Culber writes it off as insane rambling, but Tyler later snaps Culber's neck and Stamets repeats the line.
- Combat Pragmatist: Burnham defeats Mirror Connor by triggering a brief Gravity Screw, just long enough to gain the upper hand.
- Continuity Nod:
- The 23rd Century Constitution Class USS Defiant having been transported to the the Mirror Universe and back in time to the 22nd Century, and its advanced technology being one of the reasons for Terran hegemony, was revealed in the Star Trek: Enterprise two-parter "In A Mirror Darkly".
- Mirror Connor notes that the lateral vector transporters on the Shenzhou have been replaced with the newer, more efficient model. Burnham made this criticism of the Shenzhou's transporters when she and Georgiou first met.
- Crapsack World: The Mirror Universe, as is traditional. Lorca, whose morality can be flexible, is utterly appalled at what they learn of the Terran Empire, and Burnham determines that the humans in that reality live in constant fear of being knifed in the back because everyone really is out to get them.
- Dare to Be Badass: Burnham encouraging Tilly to assume her Mirror Universe persona:"Terran strength is born out of pure necessity. Because they live in constant fear. Always looking for the next knife aimed at their back. Their strength is painted rust. It's a façade. But you have the strength of an entire crew that believes in you. Fortify yourself with our faith in you. That's what a real captain does."
- Dead Person Impersonation: Burnham impersonates her presumed-dead alternate self, so she can access encrypted Terran files on the Shenzhou.
- Dressing as the Enemy: Upon learning of the vastly different Terran Empire, Lorca has the crew go all-in so they can blend in. This includes repainting the hull and interior, switching everyone's uniforms, and even reprogramming the displays.Lorca: To successfully crash a party, you have to look like you belong. You must project confidence. Every detail of this so-called Terran Empire must be replicated exactly. And wherever we may fall short, we have to get creative. Our very survival relies on our ability to maintain this cover. No matter what. We are now the ISS Discovery.
- Driven by Envy: Mirror Connor attempts to kill Burnham not only because he doesn't want to give up his command, but because he's never achieved the level of respect from the crew that Mirror Burnham had. He's proven right when the bridge crew applaud when Burnham steps over his body and out of the lift.
- Evil Has a Bad Sense of Humor: 'Captain Killy.' Enough said.
- Evil Me Scares Me: Tilly is terrified of her mirror counterpart, who is apparently a blood-soaked tyrant of epic proportions. She tells Burnham that she's now going to have nightmares about herself.
- Foreshadowing:
- Two involving Tyler: Saru's danger ganglia abruptly come out when Tyler enters the bridge, and Stamets warning "The enemy is here."
- Stamets shouting "Stay out of the palace!" as well as the comments about the mysterious Emperor are also clear foreshadowing (especially given The Reveal that his calling Tilly "captain" in an earlier episode was foreshadowing).
- A Glass in the Hand: Tyler has a brief blackout, and comes to with a destroyed glass in his hands.
- Gone Horribly Right: Implicitly, L'Rell surgically and mentally modified Voq so he could take the place of the captured Tyler and eventually be returned to Starfleet as a Manchurian Agent. This conditioning was so effective that, when she tries to use her Trigger Phrase to bring Voq back, Tyler resists and retains control.
- Hard-Work Montage: The U.S.S. Discovery is transformed into the I.S.S. Discovery, with everyone donning appropriate uniforms.
- Hold Your Hippogriffs:Burnham: Isik* for your thoughts?
Tyler: What's an isik?
Burnham: It's an old Vulcan saying. No one actually knows where it comes from.
Tyler: Must make it hard to cash in. - How's Your British Accent?: Lorca uses a Scottish accent when he's forced to pretend to be the ISS Discovery's chief engineer; Jason Isaacs is from Northern England and a Scottish accent comes quite naturally to him.
- In Love with Your Carnage: Mirror Connor clearly finds Tilly's threats attractive.
- In Spite of a Nail: Lorca says to Burnham, "Different universe, but somehow the same people had a way to find each other. The strongest argument I've ever seen for the existence of destiny."
- It's All My Fault: Lorca takes responsibility for what happened to Stamets. Culber agrees.
- Kick the Dog: Terran prisoners are shoved into an agony booth and then left there, presumably only removed as is necessary to keep them alive.
- Klingon Promotion: Tilly's counterpart became captain of Discovery by knifing her superior, and Captain Connor tries it on Burnham.
- Manchurian Agent: Tyler. Ironically, he successfully passed the Manchurian Protocol specifically meant to pick that sort of thing up.
- Memory Gambit: L'Rell attempts to awaken Voq's true identity by using a trigger phrase (reciting a prayer), but something clearly went wrong and Tyler's personality largely remains in control.
- My God, What Have I Done?: Burnham looks remorseful when she kills Mirror Connor, since she was friends with his prime counterpart.
- Mythology Gag: When Lorca has to play the Discovery's chief engineer and is warned to disguise his voice, he puts on a Scottish accent.
- Neck Snap: Tyler snaps Culber's neck after he finds out what really happened to Tyler.
- Never Found the Body: Mirror Burnham was lost and presumed dead in her pursuit of Mirror Lorca. Burnham uses this to impersonate her alternate self, claiming that she was Faking the Dead as a ploy to capture Lorca.
- No One Sees the Boss: The Emperor of the Terran Empire is unknown to the galaxy at large, apart from their cruelty.
- Odd Name Out: Mirror Tilly's nicknames include "the Slayer of Sorna Prime," "the Witch of Wurna Minor", and... "Captain Killy."
- Oh, Crap!: Tilly reacts this way when she sees that her Terran counterpart is captain of ISS Discovery, since she isn't looking forward to impersonating her.
- The Power of Love: It's implied that Tyler's love for Burnham is the only thing preventing the Voq personality from fully reawakening.
- Precision F-Strike: While not as literal as her famous first one, Tilly refers to the people in the Mirror Universe as "assholes".Tilly: Well, let's not keep these assholes waiting. (Beat) Too much?
Lorca: Not here. Here it's just right. - Properly Paranoid:
- As Burnham notes while explaining her Jerkass behavior, Terrans constantly put up a tough front because everyone really is waiting to stab them in the back.
- Burnham refuses to leave Lorca in the care of her Terran crew, believing that any one of them might let their ambition get the better of them and kill him for the bounty. As Mirror Connor shows, she's right to worry. She has to reluctantly abandon him at the brig, however, since she can't avoid sticking him in the agony booth.
- Red Baron: Captain Tilly of the Terran Empire is known as "The Slayer of Sorna Prime", "The Witch of Wurna Minor", and "Captain Killy". Saru snarks that the last one isn't very clever.
- Retcon: The U.S.S. Defiant (NCC-1764) is shown as a wireframe diagram and has several stark differences from the classic Constitution design as shown in "The Tholian Web" and "In a Mirror Darkly", suggesting either that it was modified in the century or so that it spent under the control of the Terran Empire, or that the more advanced look of Discovery will be carried forward. Without a Prime Universe Constitution-class for reference, it's hard to say for certain.
- The Reveal:
- It's essentially confirmed that Tyler is really a surgically and mentally altered Voq.
- Stamets calling Tilly "Captain" back in "Si Vis Pacem, Para Bellum" is revealed to be a result of him perceiving the mirror universe.
- Shout-Out: Culber mentions the "Manchurian Protocol" used to test for brainwashing.
- Sickbed Slaying: Mirror Tilly became captain by slaying her captain while he was in bed, recovering from the flu.
- Trigger Phrase: L'Rell speaking the phrase "Whom do we seek?" in Klingon causes Voq to reassert himself in Tyler, but it's subverted when Tyler's personality takes over again just before Voq can say his name and complete the transition.L'Rell: (in Klingonese) Whom do we seek?
Voq: (in Klingonese) Kahless.
L'Rell: How do we find him?
Voq: Together.
L'Rell: Give us light to see.
Voq: Forever.
L'Rell: Will he hide from us always?
Voq: Never. - Uncomfortable Elevator Moment: Mirror Connor tries to assassinate Burnham in a turbolift, which is about as uncomfortable as elevator rides get.
- You Are in Command Now: Lorca leaves Tilly in nominal command of Discovery.
