On this week’s Supergirl, Kara becomes a danger to her friends and National City after she is exposed to Red Kryptonite.
Cat Grant is interviewed on The Talk. She goes on record about how brave and kind Supergirl is.
Cat comes into the office and asks Kara to find Winn. Kara hears him in the supply closet, but the door is locked. She uses her x-ray vision and finds him in a compromising position with Siobhan.
Kara asks James why Lucy quit her job. He says they broke up. He says maybe he didn’t love Lucy as much as he thought he did.
Kara feels guilty. Alex tells her to let James know how she feels before someone else does.
The senator comes to the DEO to thank Hank for keeping the planet safe. She’s glad that someone she trusts is the head of the department since they’re not overseen the same way the rest of the military is.
A fire breaks out in National City due to a crashed satellite, and a firefighter is stuck under rubble on the roof. Supergirl saves him but is exposed to Red Kryptonite before she flies away.
The next morning, Kara chooses more fashion-conscious clothes for work. Cat compliments her. Kara beats Siobhan in giving Cat a list of replacements for Lucy. Cat rewards her with tickets to a club on Friday.
Hank briefs the DEO about a K’hund alien attacking armored trucks. Hank asks Supergirl to help, but she acts flippant.
The DEO goes after the K’hund when he attacks another armored car. Supergirl fights him and is winning, but tells him he’s not worth her time and lets him go. She tells her sister that he got away.
Hank comes down on Kara for letting the alien escape. She yells at him for not catching the alien himself. She accuses him of dishonoring his people. On her way out, she punches a hole in the wall.
Kara uses Cat’s elevator to come to the office. She tells Cat that using her elevator kept Cat’s latte from getting cold. Cat admires her for being brazen.
Siobhan brings Cat a video of Supergirl letting the K’hund go and tells her she should run a story on it. Cat dismisses her.
The DEO catches the K’hund who then tells Alex and Hank that Supergirl let him go.
Kara catches Siobhan trying to send the video of Supergirl to the Daily Planet behind Cat’s back. She sends Siobhan to sign for a package and prints out the email Siobhan wrote, giving it to Cat. Cat calls Siobhan a backstabbing imp and tells her she’s fired. Cat says she talked to Perry White and there’s no job for her at the Planet either. Kara is thrilled. She offers to take James and Winn dancing.
Kara shows up to the club in an amazing dress. She asks Jimmy to dance. She’s clingy and hits on him, insulting Lucy. James is upset. Cat calls and asks him to summon Supergirl for her. Kara leaves before he hangs up the phone.
Cat confronts Supergirl about letting the alien go. Kara tells her that she’s sick of being a hero and quits. Cat warns her to lay low. In a show of power, Supergirl throws Cat off the building and catches her seconds before she hits the sidewalk. She tells Cat never to call her again.
Jimmy and Winn tell Hank and Alex that they think there’s something wrong with Kara. They’ve already come to the same conclusion. They narrow the time of her change down to the fire and discover a block of manmade Kryptonite. Max shows up and admits to making it.
Alex arrests Max and puts him in a cell. Max says he’s there to help. He says he tried to recreate Kryptonite to booby-trap the satellite to take out Non. He didn’t realize Supergirl would be exposed. He offers to create an antidote. Alex lets him loose.
Cat goes on the air to warn National City that Supergirl is dangerous. James and Winn try to talk her out of it, but she asks if they can guarantee citizens’ safety. They can’t.
Alex goes to Kara’s apartment to try to reason with her. Kara accuses Alex of being jealous of her. She tells Alex that without her, she has no life and that Alex hates her for it. Kara flies off, leaving Alex in tears.
The senator tells Hank and Alex that they need to use the DEO to take Supergirl down as an alien threat. Hank assembles the troops, and Max gives Alex a gun that should reverse the effects of the Kryptonite.
DEO agents shoot at Supergirl, but the bullets bounce off of her. Alex aims Max’s gun, but Kara breaks her arm so she can’t use it. Kara tries to kill her, but Hank transforms into J’onn J’onzz to stop her. He weakens her and Alex shoots her with Max’s gun with her other arm, knocking her unconscious. The other DEO agents arrest J’onn for posing as Hank.
Kara comes to and breaks down. She apologizes to Alex. Alex admits there was some truth in what Kara said to her and they need to work on that.
The senator questions J’onn about the death of Hank Henshaw. He admits he killed him. Alex asks why he didn’t escape when he had the chance. He wanted to keep her and Kara safe.
Kara tries to apologize to James, but he says they’re not okay. He feels that she has hate inside her. She admits that she was jealous of Lucy and tries to tell him that she loves him. He cuts her off and tells her he needs time to think.
Cat walks onto her balcony to find Supergirl. She apologizes to Cat and says she’s afraid that she’ll never win the city’s trust again. Cat says it’ll take time, but if anyone can win the city back, it’s Supergirl.