Star Trek Discovery Season 3: Everything You Need To Know

Things quickly fall apart in the Mirror Universe for our heroes: Because his body is literally used to operate the spore drive, the glitch that strands the crew in the Mirror Universe also leaves Lieutenant Stamets catatonic.

The presence of L'Rell triggers memories in Ash Tyler and he's revealed to be a Klingon sleeper agent in disguise, killing Doctor Culber when he's discovered. Worst of all, Captain Lorca is outed as having originated in the Mirror Universe and deliberately stolen the Discovery to overthrow Emperor Georgiou because he believes she's not fascist enough.

As Michael grapples with the fact that her kinda-sorta-BF is in fact a Klingon (you know, the guys who killed parents) and also has to deal with meeting the dark counterpart of her beloved former captain, Lorca attempts to overthrow Georgiou. A big fight scene breaks out resulting in Georgiou throwing Lorca into a fire pit, but the coup continues and the Emperor faces certain death.

Thankfully, Stamets recovers and pilots Discovery back to its own reality. In a bizarre attempt to atone for what happened to the original Captain Georgiou, Michael rescues the soon-to-be-deposed Emperor, taking Georgiou against her will back to Discovery as the ship flies to safety.

Discovery returns its home universe, but in its absence and without the tactical advantage of the spore drive, the Federation has now all but lost the war with the Klingons.