The biggest twist from Star Trek: Discovery Season 1 has returned for Season 3. After living in the Prime Universe since the end of Season 1, Phillipa Georgiou, former Terran Emperor in the Mirror Universe, has been confronted with the very real prospect that she might need to go back to where she came from in order to stay alive. But what’s really going on? In “Terra Firma, Part 1,” Discovery has taken a very unexpected turn, seemingly in the middle of several other storylines, to fully tackle the mystery of fixing Georgiou’s “problem.” And that means that we’re now in a position where we have to unpack her Mirror Universe 2250s timeline to really get a sense of what the hell is going on. Here’s a rundown of Georgiou’s Mirror Universe timeline, as we understood it in Season 1 of Discovery, and what has fundamentally changed in Season 3. Although the title should have been a dead giveaway, “Terra Firma, Part 1” takes a shocking blind turn back into the Mirror Universe, set just before the timeline as Discovery Season 1. After the A.I. of the USS Discovery’s computer advises the ship to take Georgiou to a planet in the Gamma Quadrant, Burnham and Georgiou meet a mysterious man named Carl, who encourages Georgiou to step through a Narnia-style portal that could double for that doorway you’ve seen in the intro to The Twilight Zone.

When is this taking place?

Seemingly, Georgiou has not only traveled back to the Mirror Universe but also back in time to events that occurred offscreen well before Discovery Season 1. At this point in the Mirror timeline, the ISS Discovery hasn’t exchanged places with the USS Discovery, and it seems, Mirror Lorca hasn’t even left the Mirror Universe yet at all. Instead, we’re at a point somewhere in the Mirror version of 2255 and a time when Georgiou’s new flagship, the ISS Charon, is about to be christened. How do we know it’s 2255? In Discovery Season 1, in the episode “What’s Past is Prologue,” Lorca tells his followers that they’ve endured “one year and 212 days of torture.” Because that episode takes place in roughly 2257, it seems likely that his coup against Georgiou and his subsequent accidental transposition of the Prime Universe happened roughly two years before that. In the Prime Universe, in 2256, Lorca and his ship the USS Buran was destroyed, and, by that time, Mirror Lorca had replaced Prime Lorca. But, Georgiou has gone back in time before all of that happens. In the Mirror Universe, Lorca doesn’t go on the run until after his coup is discovered, which means, right now, there’s not even the right setting for him to trade places with this counterpart.

So, could we see Prime Lorca enter the Mirror Universe?

Assuming Mirror Lorca goes on the run, encounters an iron storm, and swaps places with Prime Lorca, sure. It’s possible. But, it also seems pretty unlikely, mostly because the events set into motion by Georgiou returning to the past have already significantly altered the way history played out before. In “What’s Past is Prologue,” Lorca explains to Mirror Stamets exactly how he entered the Prime Universe, basically on accident. That exact same accident or a similar accident has to happen in order for Prime Lorca to swap places with Mirror Lorca “again.” And, as mentioned before, Georgiou has popped back into a point in history way before that happened anyway. 

Wait. Didn’t Mirror Stamets die a different way before?

Correct! In “What’s Past is Prologue,” Mirror Lorca had Mirror Stamets executed. But, now, in “Terra Firma, Part 1,” Georgiou kills Stamets before he can betray her to Lorca. This is nuts on a few levels. First, in the original Mirror Timeline, Stamets ended up double-crossing Lorca, and tried to remain loyal to Georgiou; this, to some degree, is why he was killed. This is also relevant because, in Season 1, Mirror Stamets’ experiments with the Mycelial Network were partially responsible for helping Prime Stamets understand the network. The Charon was the central hub of Mirror Stamets’ experiments, but now that he’s been killed before that can happen, it stands to reason his research has been halted, too.

Okay, so has Georgiou created the Mirror-Mirror Universe?

Because Georgiou has killed Mirror Stamets, she’s already created a new timeline. If she succeeds in keeping Mirror Burnham on her side, and preventing Lorca’s coup before it begins, then, in theory, everything is now happening in a new timeline, a new universe. This time, she remains Emperor of the Mirror Universe, and that timeline goes in a very different direction. 

The Kelvin Universe from the reboot films is a good model to help with this headache

Assuming Georgiou is really back in 2255 of the Mirror Universe, that doesn’t mean that there isn’t still a version of the Mirror Universe that still played out the same way as before. It also follows that everything in the Prime Universe did happen the way it did before, otherwise, Georgiou couldn’t even be in this situation, with these memories at all. When Nero destroyed the Kelvin in Star Trek 2009, he didn’t erase the Prime Universe in which Kirk’s dad lived, he just created a new timeline. Ditto for Georgiou. So yes, it seems like she’s created the Mirror-Mirror Universe. (You know, like the TOS title “Mirror, Mirror.”) On top of creating a new Mirror Universe, Georgiou has also, probably, created an Anti-DISCO Prime Universe. Because if Prime Lorca and Mirror Lorca never swap places, then that version of the Prime Universe, again, would eventually, be totally destroyed by Control, probably. That is, assuming Control even rose to power at all. The Klingon War would probably be won by the Klingons in this new Anti-DISCO Prime Universe if the Prime events of Discovery Season 1 don’t happen the way they did before. One way to look at this is that Lorca and Georgiou are kind of like Donna Noble in that Doctor Who episode “Turn Left.” But, instead of Donna turning left in a car, Georgiou stabbed Stamets in the neck.

Is this actually happening? Or is this a “dream”? (Or a low-rent Nexus?)

It seems like this trip to the Mirror Universe is legit. However, there is one little question that doesn’t quite have an answer yet. If Georgiou was sent back to the Mirror Universe, at this specific time, what happened to her “original” self? The Georgiou we see here has the same bracelet that Culber gave her from the Prime Universe version of 3188. She has the memories of everything she’s done and everything that’s happened in both universes since she left. Presumably, if she’s “literally” the same person she was in when she walked through Carl’s doorway, she’s like two years older, maybe a little more. What happened to the two-years-younger Georgiou from Mirror 2255? Did she swap places and end-up on the snow planet with Michael Burnham?  In the Star Trek: Voyager episode “Relativity,” we learned about a way in which a time-traveling future Starfleet dealt with this problem: Basically, they forced conflicting versions of the same person into a process called “temporal integration.” This means, in theory, Mirror Georgiou from the “present” could have been “reintegrated” with Mirror Georgiou from the past. If Carl’s magic doorway can send her back at all, then it seems like it could also “reintegrate” her with her past self, too. The other option is that this method of time travel is a loosey-goosey style of time travel kind of like the Nexus from Star Trek Generations. In that movie, Picard was able to return to the exact point in time he needed to, complete with his memories of how it had gone the first time. Nobody worried about what happened to the “first” Picard who got his ass beat by Soran, because Nexus Picard was magically back, and he had Nexus Captain Kirk with him to throw some extra punches.