WARNING: The following article contains spoilers for the midseason premiere of Star Trek: Discovery, "Despite Yourself," which debuted Sunday on CBS All Access.
Star Trek: Discovery's midseason premiere, "Despite Yourself," confirmed tonight that the Starfleet vessel did indeed wind up very far from home when it made that final jump in November's winter finale. Instead of completing the relatively small jump back to Starbase 46, after Captain Lorca entered in new coordinates at the last second, the ship wound up in an entirely different universe. The Mirror Universe, to be exact.
Introduced in the Original Series episode "Mirror, Mirror," the Mirror Universe is an alternate reality in which humanity exists as a race of bloodthirsty conquerors who believe in racial purity and the overall superiority of the human race. It's basically an entire universe made up of everyone's evil twins, and fans have been relentlessly theorizing if and how it would manifest on Discovery, as rumors persisted it might.
While the showrunners remained understandably mum on that topic, they teased the journey with a trail of breadcrumbs that begins as early as Episode 3. Discovery has earned a reputation for deep-cut references to Star Trek's extensive canon, and that's evident in the subtle clues sprinkled throughout the first half of the season hinting that a visit to the Mirror Universe was on the horizon, and that the visit was going to be orchestrated by the ship's captain.
In Episode 6, "Lethe," Captain Lorca (Jason Isaacs) reunites with his erstwhile lover, Admiral Cornwell (Jayne Brook). When she begins to imply he's not mentally fit to return to duty after having been imprisoned by the Klingons in "Choose Your Pain," he cleverly sleeps with her in an effort to distract her from psychoanalysis. Afterward, as they lie in bed, she notices a mysterious triangle-shaped scar on his back, and when she touches it, he jolts awake and attacks her.
The shape of the scar is significant because it looks remarkably like one that might be left by a personal agonizer, a Mirror Universe device that inflicts intense pain when applied to a subject. They were portable versions of Agony Booths, torture chambers big enough to house an enemy alien or a wayward crew member; the Imperial Starfleet isn't a fan of sparing the rod. It could certainly explain why Lorca had such an extreme reaction to her barely touching that spot on his back.