Warning: spoilers ahead for Episode 20 of Supergirl Season 2, "City of Lost Children."
Supergirl introduced a brand new baddie in Season 2 with Queen Rhea of Daxam. She was introduced as a woman who loved her husband and wanted nothing more than to bring their son back to rebuild Daxam; unfortunately, when Mon-El chose Kara and Earth over his parents and Daxam, Rhea... didn't take it so well, murdering her Herculean husband and deciding that she would take her son back, even if that meant taking Earth. She made an alliance with Lena Luthor, and in "City of Lost Children," we discovered just what they were working on: a portal. Rhea used the portal to bring a Daxamite armada through space to Earth for an invasion, and Kara is in serious trouble now.
Obviously, Kara's most immediate problem is the fact that there are dozens upon dozens of Daxamite ships that have descended on National City with the singular mission of turning Earth into New Daxam. The promo for next week indicates that we'll be getting the CW version of Independence Day courtesy of the Daxamites, and something tells me that Kara might not have a Bill Pullman-esque speech ready to go. The Daxamite invasion really might be the worst thing that could have happened to Kara at this particular juncture.
For one thing, when Rhea fled the scene before Kara could capture her, she took Lena with her. Now, she has a hostage that Kara cares about very much and a genius whose brilliance helped her create the portal that brought the Daxamites through to Earth. Sure, Lena thought that she was helping to send Rhea home rather than bringing a Daxamite armada to conquer Earth, and she definitely didn't seem inclined to do Rhea any favors after she figured out the duplicity, but captivity can do crazy things to characters.
Could this be the inciting incident that causes Lena to embrace her inner Luthor and come to see her brother and mother's points of view on aliens? It's quite possible that Lena's love for Supergirl might not be enough to keep her sympathetic to aliens after being tricked into facilitating an alien invasion. Given that Katie McGrath has been promoted to regular status for Season 3, if Lena does turn, she'll be able to battle Kara for a while.
For another thing, "City of Lost Children" revealed that Kara may not be able to count on Mon-El in the battle against the Daxamites. He may have chosen Earth and Kara when he was faced with the prospect of returning to Daxam, but he just proved himself unable to stop his mother, even knowing the awful things she'd done and was doing. Of course, he might change his tune when he discovers that she murdered his father; we'll have to wait and see. As it is, Kara might not have the firmest of allies in Mon-El.
Then, there's the fact that Rhea has the tech that allowed her to incapacitate J'onn, who is one of the most powerful characters ever introduced on Supergirl. If Rhea takes him out of the game, Kara will be down a very valuable ally. Although Alex, Winn, and James are all heroes in their own right, they're very much human, and all the cool toys and suits of armor may not allow them to hold their own against the Daxamites for too long. Basically, Kara is going to need a bit of a miracle to save the day this time.
Well, the promo showed Cat Grant back in the action, so at least Kara will have a source of pep talks. Superman will be back soon as well. We're in for an action-packed last couple episodes of Season 2. Tune in to The CW on Mondays at 8 p.m. ET to see what happens next on Supergirl, and don't forget to check out our summer TV premiere schedule to discover all your viewing options now and in the coming weeks. Be sure to drop by our rundowns for cable/streaming and broadcast TV renewals and cancellations as well. Our TV season finale schedule can give you all you need to know about your shows ending.