Jonathan Frakes has spilled the beans regarding a major sub-plot in the upcoming Star Trek: Discovery series. The latest iteration of the Star Trek franchise will see the Enterprise return to CBS, bringing the decades-long property into the streaming age. CBS has made sure that storyline secrets remain hush-hush, but the actor and director — who gained fame as Commander Riker — could not control himself and recently shared a major bit of Star Trek: Discovery’s storyline.

Warning: Spoiler Alert!

Frakes shared with fans a major sub-plot involving the mirror universe in the Star Trek: Discovery timeline. This behind-the-scenes info was shared during the cast reunion at the Continuing Voyage Convention tour stop in Chicago. Once Frakes had shared the information with a handful of die-hard Trekkies and Trekkers, it was only a matter of time before the details appeared on Twitter. It was members of the Star Trek-themed cover band 5 Year Mission who took to social media to share the news.

And Fark of 5 Year Mission confirmed to Trek Movie that Frakes had promised fans a return to the mirror universe. Frakes, still in the inner circle of Star Trek, has signed on to direct at least one episode in Season 1 of Discovery. This wouldn’t be Frakes first rodeo, as far as directing a Star Trek-related property. He has directed the films Star Trek: First Contact and Star Trek: Insurrection, and he showed up in cameo roles in Star Trek: Deep Space Nine and Star Trek: Voyager.

The mirror universe has been a part of Star Trek lore since the first series in the 60s. In this alternate timeline, Kirk, Uhura, McCoy, and Scotty meet their doubles face to face in a mirror world where the Terran Empire takes the place of the Galactic Federation. In the episode “Mirror, Mirror,” the mirror universe plot element was born, but it has shown up in Deep Space Nine and in the comic book version of Star Trek: The Next Generation from IDW Publishing.

The new series will be the first major Star Trek property with a TV-MA rating. No worries, though; producers have promised that in keeping with the tradition, the series will be suitable to be shared from parents to children and sibling to sibling as it has been for generations.

Tomorrow is @startrekcbs premiere! We’re FINALLY there! Here’s another #BTS 2 get u excited! RETWEET & get ppl talking! Shenzhou opps! pic.twitter.com/eObgBqvzQ3 — Ted Sullivan (@karterhol) September 18, 2017

The series kicks off with a two-parter that can be streamed via CBS All Access at 8:30 p.m. ET/5:30 p.m. PT. Part two of the two-hour premiere will be exclusively available on CBS All Access at 9:30 p.m. ET/6:30 p.m. PT.

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