Trama

Brainiac-5 and Nia time-travel to 2009 Midvale to get a sample of Kara's DNA.

Nia and Brainy attempt to save Supergirl from the Phantom Zone by time traveling back to Kara's home in 2009. While determined to secure the item needed to help Supergirl, Brainy is worried about keeping a low profile so as not to alter the future timeline. However, when their ship crashes upon arrival, a young Kara Danvers is the first on the scene. Meanwhile, a young reporter named Cat Grant sets her sights on Midvale as she suspects there is a big story in the small town.

At the tower, Brainiac-5 and Nia show John and Alex a copy of the Midvale Weekly, the week of the high school prom. Alex remembers that she was home from Stanford, and during a meteor Kara flew up to deflect a Kryptonite meteor, got hurt, and fell into the roof of the gym. No one saw Kara, and Kara's hand was cut.

Brainiac-5 calculates the exact location of Kara's DNA: the center field of the high school's baseball field. As Brainiac-5 goes to get his things, Nia points out an article in the newspaper about how Midvale is the "luckiest" town. Alex explains that Kara and her boyfriend Kenny Li became a "Scooby Doo" team, saving kids and rescuing cats from trees. Kenny died pre-Crisis, but is alive now. John suggests that there could be other post-Crisis changes and he go with them. Brainiac-5 comes back and says that John's presence could increase the chance of history being changed if he or Alex runs into his past self. Brainiac-5and Nia were the only two who weren't there, and Alex tells Brainiac-5 not to change up her history.

In the Legion cruiser, Brainiac-5 and Nia dress for the 90s and Nia remembers her childhood. She points out that Brainiac-5 is stress eating again, and asks if he's worried about the last time he time-traveled, he was off by 12,000 years. Brainiac-5 admits that he doesn't know what else to do, and Nia assures him that nothing bad will happen.

Before they depart, Brainiac-5 gives Nia a pair of glasses to wear.

Midvale, 2009

Kara, Alex, and Kenny are eating at a diner. Kenny goes to get a shake, and Kara says that she hasn't decided to go to National City College. As Kara says that she hasn't found the right time to tell Kenny, she hears a meteor crashing toward Earth and the baseball field. Kenny returns with the shakes and Kara says that they have study group. Alex realizes that Kara is lying, and Kara admits that she and Kenny have secretly been helping the authorities. Alex worries that Kara will endanger her and her family, and insists on driving them to the baseball field.

As the trio leaves, Cat "CJ" Grant arrives and asks the cook to make her a non-fat double latte. She says that she drove three hours from Metropolis to do a story on Midvale, and demands coffee.

Nia and Brainiac-5 arrive at the field, and Brainiac-5 says that they're time-relay field is broken. Nia points out that they're a day early based on a nearby billboard, and Brainiac-5 realizes that their prom "costumes" are useless. Nia tells him that they have 24 hours and all they have to worry about is not being seen. Kara, Alex, and Kenny arrive and Kara asks them if they came out of the spaceship. She overhears them and wonders how they know her name, and they says that their psychic aliens. Once they step aside, Brainiac-5 tells Nia that they need to get the trio out of there. Off on their own, Alex says that they have to get out of there but Kara wants to help them and Kenny sides with Kara.

Kara goes over and introduces herself, and Nia and Brainiac-5 introduces themselves as "Brenda and Brendan." Nia claims that they left their destroyed planet, and only have one day to meet up with their fellow teachers. Brainiac-5 lists they need, including the rare earth dysprosium. Alex says that there may be a dysprosium geode at the university that her mother is studying.

Using her super-hearing, Kara hears police coming toward the field. She tells the others and they figure that they have to hide the cruiser. Nia and Kara combine their powers and cut up a piece of the tarp and cover the cruiser over. Kara, impressed, invites Nia to stay with them and Kenny insists that Brainiac-5 stay with him.

A spaceship orbits Earth. The alien Mitch reports to his superior Maxim Tork that he's find another alien on Earth. They had enough with Superman, but Tork figures that he needs another exhibit for his zoo.

At the Li house, Kenny is showing Brainiac-5 around his room when his mother comes in. Brainiac-5 hides, and Kenny says that he was having a study session with Kara. She has brought her son dinner, and he quickly gets her out. Brainiac-5 is hiding behind the door, and startles Kenny. He then accesses Kenny's desktop, and asks for a 3 printer. Kenny explains that 3D printers aren't common on 1990 Earth. He suggests that they go to the school's STEM lab and steal everything Brainiac-5 needs.

In Kara's room, Nia sets up a bed for Nia. Kara asks her about her family, and Nia say that her mother passed away before they had to flee. Kara says that she lost her mother, and shows Nia her mother's necklace and says that she remembers her mother. However, having an Earth family isn't the same as having people who could understand her. Nia figures that if she could talk to her mother, she'd have the confidence to keep going.

Kara asks what Nia's powers can do, and Nia conjures a dream-energy bubble. Kara shows Nia how she can fly, and Nia envelops her in her sphere. Alex comes in and wonders what they're doing, and says Kenny just texted and are fixing the time-travel device while they use their mother's ID to sneak into the university and steal the geode. Nia thanks Alex and Kara for helping them, and Alex leaves. Kara says that Alex can be a control freak, and they go to bed.

Nia has a dream of a Midvale High School sign and a pink cougar in a cage. The cage opens and the cougar lunges at her.

The next morning, Nia wakes up from her dream. Kara and Alex come in and Alex shows Nia the badge and says that they have to go before their mother notices.

At the STEM lab, Brainiac-5 gets the parts he needs. Kenny says that he just made a base like the one Superman has, and Kara looks up to Superman. He plans to show it to Kara after graduation and hopes she appreciates it. Brainiac-5 builds his 3D printer, but Kenny figures that it will take a while to finish and goes to get lunch.

CJ at calls Perry, her editor, and says that believe there is some super being behind the "miracles" in the town. She wants to do a story on them and surpass Lois Lane, and goes to Midvale College. CJ sees Alex swearing her mother's bad, assumes Alex is her mother, and asks her opinion on the "miracles". Alex glares at Kara as CJ describes them, and CJ says that she wants the truth. Alex quickly says that her "students" have a big project and sends them on their way, and then tells CJ that there's nothing in Midvale worth finding.

At the school, the bell ring and Brainiac-5 realizes that he's out of comfort food. He sneaks out and finds a vending machine, but the packet he selects gets stuck. Brainiac-5 shakes it to try and get it loose, and a teacher sees him, figures that he's the tenor her Glee Club leads, and Brainiac-5 has no choice but to go with her.

Alex and Nia go into the geode storage room and find the dysprosium. Nia uses her powers to open its case.

Kenny finds Brainiac-5 playing baseball. When Kenny calls Brainiac-5 over, Brainiac-5 explains that he's been recruited into baseball, math league, and other clubs. He explains that he's learned to deal with his stress by joining clubs. Kenny warns that Alex will "flip" if she learned that Brainiac-5 has joined the clubs, and Brainiac-5 says that he'll duck out on baseball after one more line drive.

As Alex, Kara, and Nia drive home, Alex tells them about CJ. A tanker truck speeds past them and Nia astrally projects into the tanker cab and confirms that no one is driving there.

On the spaceship, Mitch remote-controls the tanker. Tork figures that a Kryptonian will respond to the "emergency and they'll know who it is.

The tanker continues, and Alex drives after it. Kara speeds after it, gets into the cab, and takes the wheel.

CJ's is trying to figure out where she is, and the tanker goes past her. Nia uses her powers to get into the cab, and CJ takes a photo of her. Meanwhile, the brakes don't work and there's a school bus ahead. Nia tells Kara to use her freeze breath on the back axle. Kara does and the tanker stops. The cloaked alien ship appears overhead, and Mitch tells Tork that he's detected a Kryptonian and a Naltorian. Tork grabs a blaster rifle.

Tork fires a stun blast as Mitch holds the ship steady. Tork misses when the tanker jerks to a halt, and Mitch detects a Coluan arriving. Brainiac-5land son the road ahead of them, and Nia tries to dream about the ship while Brainiac-5 scans for the cloaked ship and detects it.

Mitch detects Brainiac-5 detecting them, and tells Tork that they have to retreat. Tork reluctantly agrees, and the ship flies off. Alex arrives in the van, tells everyone that they have to go and CJ is behind them, and everyone gets in and they drive off. CJ arrives and realizes that something was going on.

Once the time-travel device is rebuilt, Nia puts it in the cruiser's warp drive and tries to work out what her dream means. She gives up in exasperation and looks at a photo of her and her mother on her phone. Nia then calls her mother and gets her answering machine, and Nia hangs up.

Alex wants to tell Eliza what has happened, but Kara objects and says that she can fix it. Kara doesn't know how, and Alex says that it's too much to handle and they need to tell Eliza so she can reach out to the DEO. She insists that they've all had to make sacrifices for Kara, and skipped going to Europe because Eliza was worried about Kara. Alex tells Kara that if she had more life experience, and asks Kata why if she's so mature she hasn't told Kenny she's going way for college. Kara says that she'll show Alex how mature she is and storms out.

Brainiac-5 tells Kara that he has a lead on their attacker. He figured the aliens had a run-in with the DEO at some point, and secretly hacked the DEO computer to see if they've encountered similar aliens. Brainiac-5 has confirmed that Tork runs an alien menagerie and has odd-colored skin, and Nia figures that's what the pink cougar means in her dream. The database shows that the DEO captured Tork in Uruguay in three days, and the database changes. Brainiac-5 tells Nia that their actions have just changed the space-time continuum.

CJ goes to bar, drinks, and looks at the photos she took. The blue light of Nia's powers aren't in the photo. A drone is hovering nearby, and CJ compliments the bartender on his martini. CJ says that she's a journalist there on a big story. The bartender figures that she's Lois Lane, much to CJ's disgust. Going over the photos, CJ sees a shadow of a spaceship on the road near the tanker. A boy is flying a drone, and CJ goes over to him and asks if he wants to make $20.

Kenny and Kara go out into the woods, and Kenny says that he feels responsible. Kara figures that Alex is just trying to control her future, and she knows what she's doing and what she needs to do. They come to Old Man Watson's barn, and Kenny leads her in and shows her the "heroing" base that he's made for them.

Brainiac-5 scans for Tork but can't find him. Nia comes in and confirms that Alex hasn't been able to reach Kara, and says that she should have kept trying to call her mother. When Brainiac-5 asks why she risked changing the timestream, Nia says that she needed to hear her mother's voice. Brainiac-5 employs all the coping mechanisms he's learned, doing push-ups and reciting mantras, then asks Nia how she coped when she was in high school Nia says that she sang her favorite song, and Brainiac-5 asks her to demonstrate. Nia sings "9 to 5", cheers up, and Brainiac-5 smiles.

The AI reports that it's found Tork's ship, and Brainiac-5 says that they should go.

Kenny shows Kara a tree stump that was the log where they had their first kiss. Kenny says that she changed her life, and the "fortress" is their future. He then asks Kara what going to say to him.

As Brainiac-5 and Nia go out in the woods, Brainiac-5 apologizes for snapping at Nia earlier when she revealed that she called her mother. Nia tells him to forget it, and Brainiac-5's scanner leads him to an empty field. Tork drops the cloaking field on his ship and greets them, and Tork surrounds them with a force field. Mitch comes out and congratulates Tork.