Welcome back, Supergirl fans!
Previously, Kara and Lena went to Kaznia where they find that Lex has been experimenting on aliens from the DEO desert facility to take their powers and implant them into humans. Eve was one with such abilities, making copies of herself in a bid to force a reveal of Kara’s secret identity to Lena. Kara officially learned of her doppleganger and Kaznia’s plans to attack the US. She also almost told Lena the truth, but stopped at the last moment. Though she has made up mind: she is going to reveal herself to Lena.
Ben Lockwood goes on the warpath to find the alien responsible for killing his wife along with Dreamer, which leads to him neglecting his son George. He captures her, but his anti-alien views are too much for Brainy and the DEO agents, who refuse to work with him. He also injects an experimental version of Harun-El into his system. Obviously, this is going to end well. Now his son hates him.
Alex thought she was going to be a mom when she gets an adoption call. She and Kelly head to Portsmouth, but it falls through at the last minute.
Baker’s in on it with Lex Luthor and Kara’s been kidnapped after she tries to tell him about the Kaznian plot.
So let’s see what happens next shall we?
Past: Alex and Kara go for an adventure in 2007. Kara’s bummed that Alex is going to college and will miss her sister. Kara’s claps accidentally create a thunderclap. Alex wakes up in the present after a dream. Kelly thinks the dream is Alex processing her grief over the adoption falling through. Alex, however, just feels off and thinks it has to do with Kara. She then gets a call from Brainy. Kara has been taken away to a secret room. She almost escapes, but Red Daughter is waiting for her. Brainy informs Lena and Alex about what happened with Harun-El. Lena realizes that Lockwood is the key to finding Lex. She also tells them about the Supergirl clone and the Kaznian invasion. Brainy goes to collect Nia and J’onn to handle the Lockwood situation and to confess his feelings for Nia. Kara tries to reach Red Daughter, who is very brainwashed and wants to kill her. She wants Kara to admit that she’s wrong and that the American Dream is snake oil. Kara is able to overtake her counterpart and escape as she has a slight tolerance for Kryptonite.
Help: Kara flies to J’onn to get aid, telling him that Baker wiped her files and she’s screwed. It fell apart and Lex knows who she is. Alex is in danger. Kara has to deal and tell her. J’onn says that the memories are walled off. She could go insane. Kara begs him, saying there has to be a way. Alex could remember on her own. Brainy arrives and tells them that Alex is looking into Red Daughter. Lena enlists Lillian’s help and attaches a baby truth seeker to her. She asks Lillian to extract the Harun-El from Ben Lockwood. She also poisoned her and has the only antidote. Kara sneaks into the DEO to talk with Alex, telling him that the President is working with Lex. Lockwood tries to reach the President when Lena confronts him. Lena lays it out for him regarding Lex and how he played Lockwood. Lockwood doesn’t believe her and is dying from the Harun-El. She rejoins James in the car and watches as Lockwood peals out. J’onn and Brainy go to an alien raid site where Brainy is distracted over Nia. She has a vision of a little girl riding a unicorn and wolves after her. Brainy hitches a ride to the Internet and connects Amertek to Lex and the missing aliens. Nia suggests using a Wookie Gambit to get in, but J’onn vetoes it. Brainy tries to confess his feelings for Nia, but she sees the girl from her vision. Brainy pretends to be Lockwood to get Nia in. It quickly falls apart and they are captured.
Burn: Alex is looking for a solar signature copy of Kara’s. Haley bursts in and is pissed at Alex hosting an enemy combatant. Once Alex explains the situation, however, she agrees to help her and Kara. Brainy and Nia are separated from each other. Brainy is taken to be tortured or something by the Children of Liberty when J’onn breaks in and sees aliens being led in through a portal to somewhere. A hit to the head, however, “reboots” him and puts him in line with his more… emotionless ancestors. It’s very creepy, but the fight scene where he escapes is badass. Haley, meanwhile, has been on a fact-finding mission to DC and things aren’t looking great. Searching for the solar signature, however, focuses on a building. Kara leaves, telling Alex to stay behind. The apartment Kara finds eerily looks like a copy of hers, declaring that Red Daughter is stalking her. Brainy figures out that they’re draining alien power and making weapons from it. J’onn notices that Brainy is not… Brainy. Lockwood’s powers go out of control when he enters a warehouse and injects himself with more Harun-El. He finds Otis playing video games. Lena and James listen in as Lockwood talks with Otis, who tells him about Lex’s manipulations. Lex is planning “paper tigers” with Kaznia, invade the US and stop it. Otis goes to kill Otis, but James stops him. James’ powers then go out of control and Lockwood rips out the heart from Otis. Brainy goes to free Nia, but decides to send her through the portal instead. He then knocks out J’onn. Kara reads Red Daughter’s diary: finds a picture of Mikael and a drawn picture of Alex. Alex arrives and is freaked out by Red Daughter’s proximity to Kara. Alex confesses her worries about her sister. Eliza calls saying Kara arrived, but it’s Red Daughter. Kara makes a break for it.
Portal: Kara rushes to Eliza’s home. Red Daughter declares that she hates the capitalist decadence and she represents the collective. She pushes Eliza forward, puts on a suit, and fights Kara. Kara tells Red Daughter about Lex’s plans. Kara declares that they have the same powers but Red Daughter summons purple lightning, declaring her evolved. Kara lands in a crater and refuses to submit. Alex, eventually, arrives, following the sounds of the fighting. Watching it, the walls start to crumble around her memories. She gets between Red Daughter and Kara. Red Daughter hears a heartbeat and flies away before she can finish off Kara. Alex runs to Kara and listens to her heartbeat while Red Daughter watches. Kara tries to listen to her sister’s heartbeat, begging for her not to go. She has a little breakdown and begs her not to leave her. Then, like a freaking Disney film, Kara pulls the sunlight from everything around her. She wakes up and tells Alex that she missed her. Lena takes James for the Harun-El extraction process from Lillian. James refuses and Lillian sticks him with more Harun-El to stabilize him. Dreamer and J’onn are heading to the portal while Brainy watches. At the DEO, Haley gets the news of an imminent attack and the attack is in progress. It declares that Lex is a hero and has killed Supergirl.