Because Lena is a Luthor, many people assumed when she was added to the second season she eventually turn out to be a villain, but with one episode to go, there doesn't appear to be a heel turn coming yet.
And the writers are well aware of the expectations viewers had, and you have to give them credit for not creating a dull and unsurprising origin story for her. In fact, they have done a masterful job of using the preconceived notion about her to toy with audiences.
Think about it. Most people didn't believe Lena was genuinely re-branding Luthor Corp, her family billion-dollar-tech company, as a force for good because her half-brother Lex tarnished its name. And when she became buddy-buddy with Kara, most people assumed she already knew her secret identity, wasn't truly interested in being friends with the CatCo reporter/superheroine, and has been playing a long-con -- mining Kara for personal information she could one day use to take down the Kryptonian. And how about that rocky relationship with her mother, Lillian Luthor? Most people assumed it wasn't as rocky as it appeared, allowing Lena to help her mother's anti-alien organization, Cadmus, from behind-the-scenes. And each time we doubted Lena, we were proven wrong. And that's wonderful!
But the big question is: Will Lena learn Kara's secret identity in the season finale?
"I kind of hope you don’t," Katie McGrath told EW. "Part of the fun is the fact that she’s one of the only people who doesn’t know, and that gives their relationship something different than she has with anybody else. With Lena, Kara can just be Kara; she can be Kara Danvers, not the superhero. She doesn’t have this weight and this responsibility on her. All she has to do when she’s with Lena is be a good friend. So I hope you, in a way, never see it, because what you have between the two is a very equal relationship. Lena doesn’t have to be this powerful corporate leader, she can just be a flawed human being, and so can Kara. The longer that you don’t ever see that, to me, the better."
In the penultimate episode, there is an interesting moment when Supergirl asks Lillian why she hasn't told Lena that Kara and the Girl of Steel are one in the same. "Eventually, she'll find out on her own," Lillian coldly replies. "Find out that you've been lying to her all this time. And when she does? She'll hate you for it." But is that really how Lena would react?
"There’s a couple of things that go through my head when I think about this," McGrath pondered. "You realize that, at some point, she’s going to have to know. Long may she not, in my opinion, but part of me goes, well, from all that you’ve seen from Lena so far, she’s very accepting to aliens and people that are different, so why would she be any different with Kara? Absolutely she’d feel, in a way, betrayed and hurt that her friend hadn’t trusted her, but at the same time, I think she’s a very levelheaded person, so she understands that it would be difficult for Kara to ultimately trust a Luthor with that secret. Then, I also think that Lena tries so hard to be so different from the rest of her family that that would carry over into that relationship, that she wouldn’t want to be Lex, she wouldn’t want to be Lionel, she would want to be who she has been so hard striving to be up until this point. I’d like to think she’d be very accepting of her best friend and the fact that her best friend is different."
Supergirl (Melissa Benoist) challenges Rhea (guest star Teri Hatcher) to battle to save National City. Meanwhile, Superman (guest star Tyler Hoechlin) returns and Cat Grant (guest star Calista Flockhart) offers Supergirl some sage advice.
Glen Winter directed the episode with story by Andrew Kreisberg & Jessica Queller and teleplay by Robert Rovner & Caitlin Parrish.
Distributed worldwide by Warner Bros. International Television Distribution, SUPERGIRL is executive produced by Greg Berlanti (Arrow, The Flash), Ali Adler (The New Normal), Andrew Kreisberg (The Flash, Arrow) and Sarah Schechter (Blindspot, The Mysteries of Laura). Supergirl is based on the characters created by Jerry Siegel and Joe Shuster and appearing in DC Comics, by special arrangement with the Jerry Siegel Family.