A blink-and-you’ll miss it shot in a new trailer for Star Trek: Discovery season 5 suggests that we’re not done with the Mirror Universe…

Starship Enterprise in Star Trek: The Original Series

We knew Discovery was different from the start. Pitched as a prequel to The Original Series, the first two seasons of Star Trek: Discovery had a ton of references to the first Trek series, including Michael Burnham as Spock’s adopted sister, which also meant appearances from Sarek and Amanda Grayson (no Sybok, though, sadly), as well as Kirk’s predecessor Captain Pike.

The most audacious connection to The Original Series came with the revelation that Discovery‘s Captain Gabriel Lorca came from the Mirror Universe, that evil alternate dimension first introduced in the TOS season two episode “Mirror, Mirror.” In that 1967 episode, written by Jerome Bixby and directed by Marc Daniels, an ion storm disrupts Kirk’s attempt to beam back to the Enterprise, causing him to materialize abroad on the alternate-universe ISS Enterprise, part of the Terran Empire.

While Discovery‘s first season did visit the Mirror Universe, where they found a bloodthirsty version of Tilly and Empress of the Terran Empire Philippa Georgiou, Michael Burnham and her team never encountered the ISS Enterprise. But that might be about to change…

At the end of Discovery‘s season five premiere “Red Directive,” viewers saw a brief trailer teasing the remaining episodes. Most of the images involved the usual decontextualized quotes, familiar characters shooting or avoiding phaser blasts, and various character shots (including the return of Tig Notaro’s Jett Reno!). But one keen-eyed viewer caught a glimpse of something very interesting among the array of images.

After the account The Art of Star Trek posted the playful tweet about “a flash of something intriguing in this trailer,” user Christian Schlieper got more direct: a Constitution-Class starship peering through the mist. User JazzyParallax followed up with a more thorough explanation, noting that “There’s a chance it might be the ISS Enterprise.” As proof, JazzyParallax argues, “On the first screenshot you can read « 1701 », and in the trailers there are shots of the Terran Empire emblem in SNW’s sickbay. And S05E05 has a name that adds up to this theory.”

As Discovery star Sonequa Martin-Green revealed to Den of Geek magazine, she and the producers did not know that season five would be the series’ last when they began work on it. For that reason, the Mirror Universe might be bringing the series full circle, while the ship also explores the Progenitors introduced in the Next Generation episode “The Chase.”

There’s a nice thematic echo as the show closes up its run. Outside of paving the way for the wonderful Star Trek: Strange New Worlds, the first two seasons of Discovery were full of controversial decisions and sudden tonal shifts as the show tried to find its footing. No one would blame current showrunner Michelle Paradise for ignoring those rough patches altogether. But if indeed that’s the ISS Enterprise, then Discovery‘s wink at TOS and its first season serves as a nice recognition of how far the show has come. Because, to paraphrase another controversial prequel series that changed focus after two seasons, it has been a long road, getting from there to here.

Star Trek: Discovery is now streaming on Paramount+.