Carter and Zoe come across Jo pounding drinks at Café Diem. Carter wants to know why she's so nervous. Jo says it's because it's the school science fair—the most dangerous day of the year. Carter is skeptical, but Jo says "It's Armageddon, with acne." Carter asks Zoe what her experiment is. It's the Mendel fly genetics. Zoe is prepared to be humiliated by the competition. Vincent says Zoe's just nervous about her IQ test. IQ test? This is news to Carter. Zoe says there was no point telling him; nothing can be done about it. Carter says he could have told her that he'd had to take one, and that it wasn't so bad. He didn't even try and he got 111—over 100%! Vincent, Jo, and Zoe stare. Allison comes in, getting two cups of "workout fuel" for herself and Dr. Stark. A jealous Carter orders one too, and tells Allison that he works out all the time. She doubts him, so now he has to go to the gym to prove himself.
At the gym, a very pasty, puny-looking Carter is discussing the science fair with Stark and Allison. Carter thinks everyone is blowing this science fair way out of proportion, till he sees out the window something falling from the sky and landing on his sheriff's vehicle.
Henry swings by to help Carter sort out what fell on his truck. Henry suggests it might be a meteorite. Whatever it was fell through his engine block and bored a hole quite deep into the ground beneath the truck. It looks like a piece of metal, and the trajectory makes it look like it was a meteorite. Carter uses an electromagnet to pull it out. Henry tells him to take it to the NEAT labs. Carter thinks the labs are all neat! No, Carter, the Near Earth Asteroid Tracking lab. Henry is all set to tow the truck to his garage to check it out. Carter wants to know how he's supposed to get around. Henry says don't worry; he called GD and Fargo is "working on something." Up rolls a tiny Smart-Car-looking thing that speaks to him in S.A.R.A.H.'s voice. There's no steering wheel—the S.A.R.A.H. car is self-navigating. Carter is reluctant, but gets in the car.
Jo, in full-on protective gear, is patrolling the science fair, discussing what happened to the sheriff's car with the principal. The principal tells Jo there's no way a student could have caused the incident, because the science fair has very strict safety rules now—including a ban on the use of GD technology. A group of snotty girls Jo refers to as The Heathers walks up. Jo thought they were supposed to be suspended after the disaster they caused last year. The principal says they considered it, but the girls' contributions have been way too valuable. The lead Heather (Megan) is mocking Zoe's fly genetics project. "Very '111,'" they say, mocking Sheriff Carter's unwitting boast.
Carter's S.A.R.A.H. car is freaking him out with its reckless driving. When he complains, the car accuses him of being uptight and gives him a massage. He screeches to a stop after nearly hitting some geese that are flying across the road. He hops out and a distraught Taggart runs up, yelling at the geese that they're flying the wrong way. Taggart refers to himself as the geese's mama. Carter corrects Taggart, saying he would be the papa. Taggart reasserts he's the mama, because in the animal kingdom, the males are useless at child-rearing. Carter concedes the point, and gets back in the car, muttering about all the crazy stuff that's going on in Eureka today.
Carter and Allison step out of the Global Dynamics elevator and Carter is immediately knocked flat on his back and pinned to the floor by an unseen force. A female GD employee walks up and explains it's the security system—a DNA scanner has registered that Carter doesn't have clearance for that level and initiated a light-based immobilization field. Allison says she thought the bugs were worked out of the system months ago. The employee says they were, but Carter must not be in the system. Didn't he get the registration notice he was sent? He says Jo opens all the mail. The light bulb goes on, and he says of Jo, "She's so mean!" He gets a temporary pass and walks up to the roof.
On the roof, a harassed-looking geeky guy—Dr. Finn—is fooling around with some kind of telescope with a camera. He rattles off some incomprehensible geek speak about it being calibrated incorrectly, so "you can imagine the kind of day I'm having." Carter has no idea what all that meant, but acts sympathetic anyway. Dr. Finn is not pleased about having to look at Carter's little rock on top of dealing with his telescope issue. He tells Carter it's probably a fragment of a Chinese weather satellite. Just as soon as the guy tells Carter there's nothing to worry about—this sort of thing happens once in a lifetime—another object streaks through the sky overhead and crashes into the earth.
Henry and Finn are in the field with Carter using a complicated 3D imaging system to figure out what the object was that crashed into the earth. They determine it is a space toilet, discarded from the International Space Station years ago.
Back at the lab, they check out the sky and see yesterday's image: a whole debris field in stable orbit. Carter asks Finn to check the latest image. Finn discovers that somehow the trajectory has been altered and it's all headed to Eureka.
At Global Dynamics, Carter and Allison are discussing a plan. Carter wants to cancel the science fair and evacuate the whole town. Allison doesn't think that'd be smart, since they can't accurately predict the path of the space debris. She tells him the safest place is the school—it was designed to be a shelter.
Elsewhere in GD, Taggart is holding and comforting a goose, tearfully murmuring about having failed it. Then he cracks its neck. Carter is very disturbed, until Taggart rips the goose open—it's mechanical. Carter wants to know why Taggart built a flock of robo-birds. Taggart explains he modified a military design in order to study migration patterns. Carter is shocked that the military is building killer geese, but Taggart explains that heavily armed flying drones, disguised as harmless geese, are perfect for warfare. He trudges back to the lab to figure out why it was flying the wrong way. The remainder of the flock tags after him, honking noisily.
Carter and Henry discuss the possibility that someone has figured out how to weaponize existing space debris. Henry says they tested this theory using giant magnetic panels in the Nevada desert in 1986, but abandoned the project right away, as the magnets erased all the recorded data (tapes, floppy disks, etc.) in Nevada. The research was shut down by 1989, which was too bad: GD, and even some of the science fair winners, were involved. Carter finds that Dr. Finn had won an internship at Global Dynamics for his science-fair project on "giant space-junk-sucking magnets" in 1986. Henry corrects him: "optical aiming devices…for giant space-junk-sucking magnets."
Carter visits Finn on the roof, asking him if it's a coincidence that the project that launched his career could be what's causing the trouble now. Finn is very bitter about his whole science fair experience, but insists he is trying to protect Eureka, not attack it. Taggart runs up to them, all excited that his geese are flying. Then the geese turn toward the three of them, apparently in attack mode. They duck indoors and shut the door just in time, as the geese slam into the door.
Carter asks Taggart if it's possible the same thing that's attracting the space junk is also screwing up the birds. Taggart explains there's no metal in the birds, but Carter presses him about the compass technology, which Taggart admits could be affected by a giant magnet. Finn is defensive, saying his project is a camera, not a magnet. Carter decides it's time to go to the science fair.
At the fair, Zoe tells Jo her flies are gone. Jo knows the Heathers sabotaged her. Zoe says ever since she got a 94 on her physics midterm, those girls have been out to get her. Jo's impressed; a 94 at a school for geniuses is quite impressive. Jo advises Zoe not to give up; she needs to get even.
Finn asks Carter, en route to the school, if he can't afford a whole car. Finn tells Carter the 1986 science fair was the high point of his career, and he is not eager to go back to school and see how far he's fallen.
At the fair, Stark is cruelly telling a student he doesn't have what it takes to be a scientist, and he should just give up. The Heathers display their project—some kind of environmentally friendly x-ray machine. They smugly fire it up for their demo, and it starts sucking every metal object in the room into a rotating cloud above the machine. Carter unplugs the machine and is ready to haul the Heathers in for questioning. Principal Wallace walks up and demands to know what's going on. Megan (the lead Heather) says Reno 111 has just messed up the future of medicine. Zoe stands up and says it's not her fault. Whatever happened is the Heathers' fault.
Jo explains the Heathers sabotaged Zoe's project, so Zoe sabotaged theirs right back over lunch by juicing up their power supply—a lot. Carter figures out that the science project isn't what caused the space junk to alter course, since stuff started crashing to earth well before Zoe cranked up the power supply.
Allison and Carter discuss how to weather the upcoming storm of space debris. The Eureka residents who are at the school should stay there, and the rest will go into underground bunkers. The people will be safe, but the debris field may destroy the town.
Megan is explaining her invention's beam technology. Allison accuses her of stealing the technology from Global Dynamics—a woman named Jane Harrington used that same technology for the security system at GD. Megan knows who Jane is; it's her mother.
Allison confronts Jane at Global Dynamics about stealing her daughter's technology for use at GD. Jane denies it at first, but she's busted. She says she is embarrassed, but she had to get the system working or she was going to get fired, so she panicked and stole the technology that her daughter invented. Allison suspends her clearance and tells her she'll have to face an ethics review.
Finn runs in saying he has something they have to see. They figure out that Jane's beam, shot into the protective magnetic shield over Eureka, turned it into a gigantic magnet. This is what caused the debris field to come crashing to Eureka. It's too late to stop it now: even though the beam has been shut off for some time now, the debris has come too close to earth and gravity has taken over.
In the school, Stark's on the phone with Allison, who's at GD. He tells her that everyone in the auditorium is fine—they just need Allison to concentrate on stopping the debris.
Megan is too busy telling Carter he's an idiot to try to come up with a solution. So Carter tells Henry he wants to use the beam technology to repel the debris. Henry points out the magnet isn't strong enough to push the space junk away. Carter just wants to nudge it a little. Henry takes over, saying what a great idea Carter just had. If they alter the angle of entry just right, they can get it to burn up in the atmosphere, brilliant! Megan is being really snotty and not at all helpful, so Finn lectures Megan and Zoe about how they both invented important things (Megan's beam and Zoe's juiced-up power supply), and they need to forget competing and work together to solve this problem.
Henry rigs up Carter's goofy little car's processor to calculate and adjust the debris field's trajectory. The car's processor isn't designed for this type of work, and is overloaded. Fortunately, it solves the space junk trajectory just in time. Megan's beam—boosted 400% by Zoe's power supply modification—shoots up into space and adjusts the debris field's angle of entry. The S.A.R.A.H. car's processor conks out immediately after telling them the trajectory was successfully adjusted 32 degrees and the debris is burning up in the atmosphere.
Stark is giving a speech at the science fair. He awards first prize, and a one-year internship at Global Dynamics, to Megan. Carter comforts Zoe, saying she was robbed. She says she didn't want an internship, and she totally dodged that bullet. Stark goes on to say that Zoe won second place, and her prize is a new car!
Later, Megan approaches Dr. Finn, telling him she gets to choose her internship. She wants to work with him. He says it'd be an honor, but if she steals his ideas, he'll make her sorry.
Taggart is tearfully releasing his robo-geese into the wild. He tells Carter he figured out the problem. He made their compasses too sensitive, because he was too worried about them getting lost. Now he has to let them find their own way in the world. His babies will get lost, but that's how they learn. This seems to resonate with Carter.
Zoe thinks Carter isn't going to let her keep the car. He says yes, he actually is. He says that he learned from Taggart that dads are kind of dumb at child-rearing. He tells her he looked up his IQ and discovered that 111 isn't all that smart. Zoe tells him, "We're Carters! We're street smart!" She wishes she'd never even taken the stupid IQ test. He says he actually has her test results with him, Principal Wallace gave them to him. She opens the envelope. It says her IQ is 157, but she wisely tells her dad it's 112. He is ecstatic and gives her a hug.