We’re three episodes into the final season of Star Trek: Picard, and it continues to be a chaotic ballet of storylines. There’s a lot happening on this show. Beverly Crusher has become a frontier doctor / Robin Hood-style smuggler traveling the outer fringes of the Federation with her son, Jack Crusher, and has spent months being hunted by mysterious forces. Worf now works as a spy for Section 31 and has spent months anonymously working with Raffi to hunt down a new cell of terrorists who seem to be as mysterious as the forces hunting Crusher.

Now, Picard, Riker, and Seven have haphazardly commandeered the Titan and are fleeing through a nebula with a greasy, cruel, and mysterious Vadic (Amanda Plummer) chasing them. And in the third episode, all those plots crash into each other, and the true villain of the season appears to have been revealed.

It goes without saying that spoilers are coming, so click away now if you don’t want to know more.

It’s changelings.

If you didn’t watch Deep Space Nine, you almost certainly have no idea what a changeling is. They were the primary villain of the show (apart from Odo, played by René Auberjonois, who was a hero and main character on the show). Originally from the Gamma Quadrant, changelings built an enormous empire, the Dominion, and used their shapeshifting ability to hide their own influence as the architects of that empire. They then invaded the Alpha Quadrant, infiltrating and destabilizing the governments of the Klingons, the Romulans, and the Federation.

It was only because of some super unethical biological warfare and the threat of genocide that the Dominion finally retreated from the Alpha Quadrant and agreed to leave the worlds of Star Trek, as we know them, alone. Since then, the Star Trek franchise has studiously avoided the changelings. While it’s had no problem trotting out other familiar Big Bads like the Borg, the Romulans, and even the Gorn, the changelings have stayed safely shuttered away in the Gamma Quadrant — someone else’s problem.

Behind the scenes, there’s certainly rationale for this. Deep Space Nine is often considered the black sheep of the Star Trek franchise; it was a much darker show that focused on complex and very adult themes. While Star Trek tends to be a big space Western about the wonders of exploration and / or cool space fights, Deep Space Nine liked to ponder things like how the colonized overcome decades of institutional violence or the complexities and sometimes necessities of terrorism.

So it just wasn’t as popular a show. People who tuned in for space adventure didn’t necessarily want to tune in for stories like “adorable Ferengi teen struggles with war-induced PTSD.”

But in the years since Deep Space Nine ended, the way we watch TV has changed. Now it seems like we hunger for darkness and extreme moral complexity in our space adventures. Where The Next Generation was expertly built for the world of syndicated TV, Deep Space Nine was an attempt at a modern prestige drama a good seven years before The Sopranos kicked off the golden age of television and popularized the form. People can appreciate a Deep Space Nine reference now — where once they might have cringed and braced themselves.

And it’s fitting that changelings would be the big villain of the final season of Star Trek: Picard. Back on Deep Space Nine, the changelings and their war were used as tools to explore the potential flaws of Star Trek and its utopia-like Federation. They wiped away the veneer of flawlessness. And this season of Picard is very much about wiping that same veneer away from its heroes.

Few scenes have exemplified that better than the crackerjack one between Picard and Crusher in this episode. In the last episode, Beverly wordlessly confirmed to Jean-Luc that her son was also his son, and he spends a good chunk of this episode stewing on that knowledge before confronting Beverly in one of the best scenes of the show. These actors haven’t lost the chemistry that made their relationship so compelling 30 years ago. Gates McFadden seems to bring something out of Patrick Stewart, and he gives one of his best performances as Picard in years. There’s real fury in his eyes as he confronts her about the child she hid.

McFadden has a tough job in this scene because she has to make you believe that the very kind, if obstinate and egotistical, Beverly Crusher of The Next Generation could really abandon all of her loved ones and friends to raise a child in secret. The decision, as Crusher explains it, was rooted in fear. Crusher lost both of her parents at a very young age to a space-based disaster, her grandmother to a parasitical alien ghost in a lamp, her first husband to a Starfleet accident, and her first son to extra-dimensional god-like alien travelers. These are not all things you would know unless you were an obsessive consumer of Star Trek, and McFadden has to remind us of all of that trauma with only a few lines.

And she does. The scene works, and it’s some of the most mature and adult performances we’ve seen in Star Trek since, well, Deep Space Nine. So it makes sense it happens in the same episode we find out changelings are the Big Bad of the season. If you’re going to make your Star Trek characters this flawed and morally complex, there’d better be a changeling lurking somewhere nearby.