Prisoners on a transfer bus take their guard hostage. As they head through the streets, Supergirl stops the bus and rips open the door. The head prisoner threatens to kill his hostage, but Hank and Alex break in and take him out. The other prisoners quickly surrender. Afterward, Supergirl asks Alex if she's doing okay, and Alex says that she isn't.
The next day, Sam takes Ruby to school and Ruby asks her mother if she's okay. Sam says that she's fine and it was just a dream, and it was just a migraine. As Ruby goes into school, a boy Luke asks if she can help him with his homework. He suddenly collapses and convulses.
At CatCo, James asks Lena about an ad she approved. He says that he wishes she had told him first, and says that if they're going to disguise ads as articles he'd like a heads up. Lena tells him that it gets people to rea so it's a necessary evil. Kara comes in and notices Morgan on the TV. He's at the hospital talking about how the lead-dispersal bomb drove off the Daxamites. Now children are falling ill displaying lead poisoning, and points out that Lena built the bomb.
Alex returns home and she and Maggie talk about their issues over Alex wanting children. Maggie admits that she's never going to want kids, but she wants Alex. Alex says that she's always going to want ids, and they figure that there's nothing else left. Maggie tells Alex to say it out loud, and Alex finally tells her that they can't be together.
At the hospital, Lena and Kara find Sam there. Sam explains that Ruby's friend collapsed and she came with the paramedics. Morgan comes out and tells Lena that he's paying the medical expenses for the children. He talks about the cobra effect in colonial India and how it had unintended consequences. Morgan says that Lena wanted to be a hero and now people are paying the consequences. Kara points out that Supergirl pushed the button, and Morgan says that Lena designed the tech and poisoned children.
Back at CatCo, Lena tells Eve to call the CDC and get all of the information on the outbreak. Sam figures that there's another explanation, but Lena worries that it's true and says that she thought the bomb was safe for humans. James comes in and suggests that Lena should get ahead of the matter by stepping down from CatCo so they can report on the story. Kara disagrees but Lena doesn't, and says that the public deserves integrity from them. Lena tells James that he's in charge of CatCo, and she'll step down from L-Corp as well. Luke's father storms in and demands to see Lena, and says that Luke stopped breathing. He insists that his son matters, and vows that Lena will answer for what she did to all of the children. Once the guards take him out, Lena tells James to put their best reporter on the investigation and to hold a press conference later that day.
Later at the press conference, protestors have gathered to demand Lena's arrest. Lena takes the stage and says that she understands their anger. She admits that she doesn't know if her device hurt children. Kara hears a gun cocking and spots the father but he only has a phone in his pocket. A mother fires a gun and Lena catches one of the bullets while a security guard tackles the shooter. James is wounded by another bullet, and she yells for help.
At the hospital, the doctors remove the bullet from James' shoulder. Winn and Kara meet with James, and James points out that Lena may be responsible for the deaths. James tests the device with sensors to analyze the particulate reverse. He says that .04% of the lead didn't bond with Daxamite genes, and Winn checks to see if it's the same number. He determines that 10% of the lead doesn't bond with Daxamite DNA.
Sam takes Lena to her apartment and assures her that she's safe there. She points out that Lena gave her a break, and she wants to return the favor. Ruby glances angrily at Lena, and Lena asks if Sam would still be her friend if Ruby was sick.
Alex packs her things, and Maggie offers her a drink and invites her to dance. Alex accepts and they end up in bed together.
Kara goes to Sam's place and finds Lena alone, drinking. Lena explains that Sam is running L-Corp and Ruby is at a friend's, and Kara wonders why Lena isn't fighting the charges. Her friend says that she did it, and all she wanted to do was good. Now she's a monster that poisoned children. Kara insists that there's a chance that she's innocent, but Lena tells her that's not the real world. In the real world, everything she does hurts people. Lena tells Kara to stop believing in her because she's not worth it.
Lena passes out, and Kara stays with her until Sam gets home. They talk about Lena and how she wants people to think that she's tough. They both have been going through the public records of the sick children, and the kids are from all over the city. The women heck the families' bank records, Sam hacking the files. They all were at Delaney's Dumpling Truck for Oktoberfest.
After sex, Maggie asks Alex if she wants to give up on them for some notion she has of being a mother. Alex tells her that it's not some notion, and she always wanted to have children. She refuses to deny that, and both women wish they could change the way they feel but they can't.
Kara and Lena go to the park where Oktoberfest was and Kara secretly breaks the door open. She examines the pool with her x-ray vision and sees lead particles in it, and takes a sample. She then sends it to Winn. Winn confirms that it's a synthetic compound that when combined with waters, exhibits the same properties as lead. Anyone exposed to it would display the same symptoms as lead poisoning. Sam wonders who did it, and they check out the chlorine chemicals. Kara calls Lena and tells her that it wasn't her, and the manufacturer is Acre Lee Chemical. Lena starts at the name but then says that she doesn't know who it is.
Later, Lena goes to Morgan's office and tells him that she knows he owns Acre lee. She figures that Morgan used it to poison kids and incriminate her, and draws a gun on him. Lena says that when the mom shot at her, Lena knew that she was right and deserved to die. Morgan tells her that she needs help, and Lena says that she's thinking like a Luthor. An aide knocks Lena out from behind.
Lena wakes up on a cargo plane. She looks out the window and discovers that the plane is flying over National City. The Acre Lee chemical barrels are in the cargo hold as well, and the plane is on automatic heading or the reservoir. Morgan is monitoring the entire thing from the ground, and tells his aide to create a little turbulence. Lena tries to send a distress call, and Morgan quickly jams the signal.
The DEO picks up the signal and Kara hears Lena's voice.
Morgan tells his aide to initiate the release sequence. Lena manages to stop the barrels from dropping, while Supergirl flies to the plane and closes the ramp. Morgan tells his aide to crash the plane, Lena warns Supergirl that the barrels are treated to dissolve in water, and Supergirl tells her to strap in while she lifts the plane up. One engine blows out, and the plane splits in two from the stress. Lena falls into one half and the chemicals into the other, and Supergirl warns that she can't hold both. She yells at Lena to climb out of her half, and Lena does so. She jumps the final distance and Supergirl grabs her just as the plane half breaks away and plummets to the ground. Supergirl carries Lena and the chemicals to safety.
Morgan gives the aide a gun to shoot the control console. One he does so, Morgan says that he needed gunshot residue on the man's hand, picks up the gun with a handkerchief, and kills the aide.
Supergirl goes to Morgan's office and tells him that he's lower than she expected. He sells that he sold the company two years ago and they found the man responsible after he killed himself. Morgan suggests that the man must have really hated Lena, and asks Supergirl what that kin of hate feels like. He doesn't think Supergirl is capable of, and says that it's the real world. Morgan says that if he had an enemy that he would crush her without mercy. He says that if Supergirl thought he was her enemy, she should kill him but she doesn't have what it takes. Supergirl says nothing, and Morgan tells her to leave the way she came.
At CatCo, Lena finds James at his desk. She says that she was worried about him after the shooting, and they agree to call each other by their first names.
Maggie finishes packing, and Alex says that she didn't think she had it in herself to be happy or accepting of herself. Crying, she tells Maggie that she never would have gotten there without her. Maggie says that Alex got her to look at her past and she's stronger for it, and thanks her. They hug and then Maggie tells Alex that she's going to be a great mom, and leaves.
Kara, Sam, and Lena have a drink to celebrate, and Sam says that the antidote L-Corp has created is working. Lena thanks them for not giving up on her, and apologizes. Kara assures her that she doesn't have to when they're family, and they hug. Alex calls Kara and asks to meet with her.
Alex is drinking at the bar when Kara comes in. She hugs Alex and then calls Hank and tells him that he'll have to get by at the DEO without the two of them. Kara then tells Alex that they're going home.
As Sam tucks Ruby in, she says that Luke will be okay. Ruby says that she likes Sam's friends and Sam agrees, and they notice a hole in Sam's shirt. Sam checks her coat and discovers a bullet in it, and realizes that the mother at the press conference shot her as well... and she was unharmed.
Written by Gadfly on Nov 7, 2017