Spoilers ahead for the Supergirl Season 4 premiere. The Season 4 premiere of Supergirl kicked things off in the usual fashion: with the Girl of Steel saving the day not just in National City, but all over the world. From catching an art thief to stopping a train from plummeting off a crumbling bridge in Kaznia, Kara proved to be just as heroic as ever. The final moments of the episode, however, brought up several questions. Chief among them: What is the second Kara doing that warranted her punching her way through rocks underground? She's definitely a woman on a mission, but to what end?
Let's back up for a minute here. The second Kara was first introduced at the end of Season 3, when an aura left Supergirl’s body during her battle with Reign. So, this is only the second time viewers have seen her. This particular scene started after a bridge collapsed in Kaznia, and Supergirl raced to save a train full of passengers. At first, it seemed like it was a random incident, but there was actually good reason for the bridge's fall: Below where it used to stand, the second Kara was using her super strength to tunnel into something deep underground, unintentionally (or maybe intentionally) making it structurally unsound.
The episode ended before we could find out what it is, exactly, the second Kara is doing or what she's trying to get to, but that doesn't mean we're completely in the dark. The one clue we're given is the fact that she's surrounded by men dressed in military uniforms. These are presumably soldiers from the same military base we saw her approach at the end of last season, when she was initially (and accidentally) created. There's no telling what she's been up to since that time, or wether her intentions are pure or evil.
Shortly after the Season 3 finale, TVLine spoke with executive producers Robert Rovner and Jessica Queller about that Kara doppelgänger twist and what it means for the show moving forward. “For fans of the comics, I think they might recognize that the story we want to tell is inspired by the iconic DC Comics’ Red Son, which told an alternate origin story for Superman,” Rovner told the outlet. Added Queller: “What happened if — as a baby — Superman landed in Russia and became a hero there instead of in America. It’s an homage to that.”
Of course, this scenario centers around Supergirl rather than Superman and she's a fully grown adult version rather than a baby, but the idea itself is pretty similar. So will she be more of a friend or a foe? Right now it's too soon to tell, but knowing how these things usually work out for Kara, it'll probably end up being the latter.
It's also possible this alternate Kara is a result of the meddling real Kara did last season. After she threw her "no killing" rule out the window and lost everyone in the process, she used Mon-El's Legion ring to travel back in time and stop any of it from happening. Her good side won out, but now that this alternate Supergirl exists, could she be the darker version that Kara almost became?
Those who watch The Flash know that messing with the timeline can come with severe consequences. Perhaps Kara is about to get a taste of that firsthand.