WARNING: The following contains spoilers for Star Trek: Discovery Season 3, Episode 5, "Die Trying," now streaming on CBS All Access.

The parallel Mirror Universe has been a fixture of Star Trek since the very beginning. Since popping up in The Original Series -- goatees and all -- the twisted version of the Prime Universe has appeared in Deep Space 9Enterprise and Discovery. But it seems those crossovers will eventually hit a stopping point.

In the most recent episode of Star Trek: Discovery, Philippa Georgiou (Michelle Yeoh) is being interrogated by Federation officer Kovich (David Cronenberg). Georgiou is a crossover from the Mirror Universe, previously a terrorizing emperor for the Terran empire who was brought over into the Prime Universe by a sentimental Michael Burnham (Sonequa Martin-Green). With her comes the Terran brand of wanton and cruel behavior, a philosophy that has intrigued Kovich ever since he was a boy.

RELATED: Star Trek: Discovery's Latest Episode Showcases the New Starfleet

After destroying Kovich's holograms, Georgiou sits down with the real deal. The two bob and weave through several points, including "The Burn" and subsequent fall of the Federation. But Kovich counters that Starfleet has endured, unlike the Terrans. He then explains that, following Georgiou and the U.S.S. Discovery's journey through the wormhole, the distance between the Prime and Mirror universes began to grow. The last crossing between the two occurred over 500 years ago.

It's a huge revelation to both Georgiou and the audience. The Mirror Universe has been a part of canon for decades, and it played a key role in Discovery's first season. One of the big twists of that initial batch of episodes involved Gabriel Lorca (Jason Isaacs), captain of the Discovery. He turned out to have actually been a Terran, crossing over accidentally and taking his doppleganger's spot in Starfleet. This revelation then means that, if the show stays in the 32nd century, there is next to no chance that they run into any other Mirror universe residents.

RELATED: Star Trek: Discovery Loses a Crew Member

And that hits hard for the former Terran emperor. Though it's unknown if Georgiou ever counted on finding another one of her kind in this universe, it's clear Kovich's stating she's all alone stick with her. When Michael sees her later in the episode, Georgiou is uncharacteristically distracted, off in her own thinking. For the first time since we've known the character of Mirror Georgiou, she actually seems worried.

In the beginning of Season 3, Georgiou said she was on board Discovery to evade the bureaucracy of Section 31, hoping to take advantage of hopping from universe to universe. But in 3189, those prospects are nill, as there's no chance for her to escape and make her return home. This new reality seems to have had a profound effect on Georgiou, and may actually lead to a very different character moving forward.

Streaming on CBS All Access, Star Trek: Discovery stars Sonequa Martin-Green as Commander Michael Burnham, Doug Jones as Commander Saru, Anthony Rapp as Lt. Commander Paul Stamets, Mary Wiseman as Ensign Sylvia Tilly, Wilson Cruz as Dr. Hugh Culber, David Ajala as Cleveland "Book" Booker, Blu del Barrio as Adira, Ian Alexander as Gray, Tig Notaro as Chief Engineer Reno and Michelle Yeoh as Philippa Georgiou. New episodes of Season 3 air on Thursdays.

KEEP READING: Star Trek: Discovery - Burnham’s New Skills Are Already Coming in Handy