In this episode of Supergirl, we jump back 10 years to a time when Alex and a newly adopted Kara exist. Kara uses her speed to beat Alex to the bathroom and then whines about having to waste time in school.
At school, Kara has trouble paying attention in class and Alex shows her up by giving all the answers before she can. “Try and keep up,” she whispers. Later that day, Kara zooms up the rope in gym class and shows Alex up.
Kara accepts an invitation to go stargazing with Kenny that night. They talk and smile and almost kiss, but Kara pulls away at the last minute to tell Kenny he’s the only person in Midvale who makes her feel like she belongs.
Then Kara sneaks in the window and Alex busts her, yelling, “Before you crashed in that pod, I had a great life with two great parents, and now I have you.
The next day, Kara super-hears police scanner talk about the body of a 17-year-old male. “Great Rao,” she breathes and races to the scene, where she’s crushed to see Kenny’s body.
Kara then visits Kenny’s house to share her condolences with his parents, who haven’t recovered his telescope. Sheriff Collins kindly tells Kara that for her own safety, she shouldn’t dig around any further. Kara agrees and then heads straight to the forest crime scene. When a noise startles her, she swings her laser eyes around and almost zaps Alex.
Alex confesses that this was where Kenny secretly tutored her in calculus, and she came there to remember him. She then encourages Kara to use her powers to look for his telescope in the dark. Kara does and finds his laptop buried in leaves.
Kara wants to turn it over to Collins, but Alex suggests they check it first. It’s full of encrypted files, so they send them to Clark’s tech-savvy friend Chloe.
Then they find an email Kenny sent Mr. Bernard with a photo of him kissing Alex’s friend Josie. When Alex confronts her, Josie says she and Samuel are in love. Alex points out this is statutory rape, and Samuel needs to be locked up. Josie tells Alex to stay out of it.
While Alex calls the police, Josie heads straight to Mr. Bernard to tell him what’s going down. After school, Kara and Alex are walking home together. Suddenly, a car comes barreling at them as they’re crossing a bridge and Kara sweeps them both over the railing to hover in safety.
Kara finds Sheriff Collins at the football games and tells him it wasn’t Bernard, but they have Kenny’s laptop, and one of the other people in his pictures is likely the murderer.
Meanwhile, Kara gets an email from Chloe with the unencrypted files, one of which is a photo of Collins engaging in some sort of illicit drug deal. She calls and warns Alex, and Alex tries to play it cool, but Collins pulls his gun.
He hits redial to see where the laptop’s stashed, and Alex shouts, “The stadium! Here’s here!” before he hangs up. At home, Kara paces for two seconds before bursting out the window to fly to Alex.
She shouts for Kara, as Kara busts through a wall, knocking out Collins and hugging Alex. “I knew you’d come,” Alex tells her sister.
And then we’re back to the present, where Alex pulls herself out of hungover misery sleep to find Kara on the porch with the telescope. Alex says that was the first time she really understood what it could mean to have a sister, and Kara says it was the first time she felt like a Danver. And while she still doesn’t feel completely at home on Earth, “I feel at home with you.” They both apologize, Alex for being mean and Kara for bottling up her own healing process.
By the time the sisters are ready to leave, Alex has shaken off her gloom and insists on driving because she would prefer to avoid any accidents on their way to Midvale.