We flashback 20 years to see how Lena came to be adopted by the Luthors. I was wondering what Supergirl’s version of the father of Luthor would be. The show went with calling him Lionel most likely in honour of Smallville. Lionel is played by Bard on the Beach alum Ian Butcher. Lex welcomes Lena by wanting to teach her chess while Lilian initially is against welcoming Lena but ends up thinking Lex having a sister is good for him.
Back to the present, it is the trial of Lilian Luthor and everyone (i.e. the Superfriends) agrees that she is the worst.
The star witness is Lena who gives a damming testimony against her mom. James is worried that Lena is going to manipulate her friendship with Kara to get what she wants. But Kara disagrees and goes to visit Lena and encourages her to see her mom.
Lean goes to see Lilian who “applauds” her daughter for her testimony in court. Lilian then drops a bomb on Lena. Lena is really a Luthor as she is a product of an affair between Lionel and Lena’s birth mother. After Lena’s birth mother died, Lionel brought her in. However, Lena kept on reminding Lilian of LIonel’s affair and that is why she kept her distance and gravitated towards Lex more and more. Lilian wants to start over with Lena and it looks like Lena might be willing.
Meanwhile, Corben/Metallo received his krpytonite heart back. The next day, Corben testifies in court in what is supposed to be against Lilian but turns out to be in defense of her and her actions. Corben then uses his kryptonite heart to attack the courtroom and breaks Lilian free.
At the DEO, Maggie says Corben had no visitors but the night before Lilian had one: Lena. Lena is caught on surveillance with the kryptonnite heart and is arrested for aiding and abetting Lilian and Corben.
At CatCo, Snapper and James decide to run a story against Lena but Kara wants to believe her innocence.
In the aftermath, Kara still believes in Lena’s innocence while the rest of the Superfriends believe in her guilt. James explains to Kara how Lex and Clark were best friends ala Smallviille. Clark wouldn’t believe what people were saying about Lex even when there was evidence. James believes the same is happening with Kara and Lena. Again, Kara believes in Lena but James wants her to believe and trust in him as Guardian.
In a van, Lilian is taking Lena somewhere and trying to convince her to join Cadmus and let her be the mom she can be to him We also see the kyptonite continuing to poison Corben.
The trio arrive to a mountain facility of Lex’s that has a satellite to detect an alien invasion and has a cache of weapons to battle aliens. But Lex protected it so that it can only be open by Luthor DNA. Lena figures that is why Lilian broke her out not out of love but so she can get her hands on the weapon. Lena refuses to help but is forced to by Cyborg Superman
Speaking of which, Winn decodes the CCTV video to reveal it was Cyborg Superman not Lena that stole the kryptonite. A kryptonite alarm goes off that alerts the team to Corben’s location. Winn notes that Corben’s kryptonite is unstable because it is synthetic and is about to blow. Kara rushes off as Supergirl to save Lena.
Lilian takes Lena through the weapons cache that includes a Black Mercy and also something that Lex was working that is now complete that interests Lilian.
Kara arrives but Winn and Alex warns her that Corben’s krytonite heart is critical and about to blow. Lilian incapacitates Kara and Corben continues to use his heart to battle Supergirl. Lena is knocked out. Lilian and Cyborg Superman flees. Martian Manhunter arrives and the two escape with Lena just in time as Corben blows up.
Lena is vindicated. Snapper and James eat crow to Kara about being wrong about Lena’s innocence. James and Kara also finally come to an understanding and resume their friendship.
Later, Lena appreciates Kara’s friendship and for sending Supergirl to save her. While it looks like Kara and Lena’s friendship is strong, it would seem like the Luthor DNA is taking over as Lena recalls a childhood memory of her beating Lex at chess with Lilian looking on proudly.
Elsewhere, Alex comes out to the gang and everyone is accepting of her relationship with Maggie.
Meanwhile, throughout the episode, we see the evolution of Kara and Mon-el’s relationship. At the alien bar, Mon-el is too enthusiastic about his relationship with Eve Tessmacher.
Kara learns that things aren’t rosy with Mon-el and Eve. Eve tells Kara that during their date, Mon-el would only talk about Kara.
Later, Kara tells Mon-el she has been distant with Mon-el because she was mad at him for dating Eve. Mon-el wants to know why Kara is mad at him for dating Eve as Kara doesn’t like him. Kara doesn’t answer but at episode’s end, Mon-el comes over. Kara tells Mon-el about their differences and her first impressions of him but how that changed over time. Kara also thought she couldn’t have it all (i.e. be Supergirl and be in a relationship) but now she thinks she can. Just when it looks like Mon-el and Kara are going to kiss, the two are interrupted by a visitor from another dimension: Mr. Mxyzptlk (Peter Gadiot). Mr. Mxyzptlk declares his love for Kara Zor-el.
Finally glad that the show went there with Mon-el and Kara. Also, glad the show didn’t make a big deal of Alex coming out to the gang as it really was just a blip in the episode. Also, is Lena truly good or is she going to become a big bad?