Rivka-if-it's-Rivka accepts the candy and eats it. She licks her fingers.

Margaret smiles and takes a bite of the rest.

Rivka (Susan looks up the news story about her; it's almost certainly Rivka) hangs out with them for the rest of the patrol.

Margaret takes a selfie with Rivka, then looks up the news story.

Rivka Stievater's parents died when she was seven and she lived with an aunt. Some people speculate in retrospect that the aunt was abusive. When Rivka starscaped at age nine and took her first mods (just a safe amount of shrinking) and did some amateur glam-up, she found that her magic was plant control; her friends at school have a couple quotes about her messing with dandelions and grass. Four days after she shrank, she shrank so small she turned cryptid, grew her wings, went into a neighbor's house through a cat door, and insisted on living there for two weeks, eating bits of the cat's food and riding the cat around the house. Eventually she flew away. The neighbors, who hadn't really known who if anyone to tell about a fairy cryptid befriending their cat, finally called the cops; previously Rivka had been listed as "missing [magical]".

Well, it's good that she seems happy. Someone has to die for a cryptid to exist, so it feels especially important that their existences are nice ones.

Rivka flies away once the truck stops.

"Quiet day today. Maybe Rivka was good luck." she jokes afterwards.

"You laugh, but some people think so!" says Charity.

"It was nice to get a visit, regardless."

"Poor kid," says Caroline. "It's sad when it's an accident, but when it looks like somebody did it on purpose -"

"Yeah. It looks like she didn't leave a note, but that could just mean she didn't have anything to say, or didn't think anybody would understand."

"She was nine," says Susan. "Is nine, I guess. Poor thing."

"I just hope she's happy . . . she looked like she was doing okay, and it's probably pretty easy to get food and shelter when you're that small."

"Yeah. She probably just lands near people and they offer her bits," says Charity, "like you did."

"Seems pretty likely."

And they all go their several ways.

Margaret sits with a different random person at lunch every day, and keeps delivering a couple prophecies a week to her CDC contact. Not as many as over the summer--she's back to getting occasional ones about swarms during patrol--but enough that she doesn't feel bad about taking up some of the contact's time.

The contact seems to think it's worth it too.

Eventually her bacteria and bacteriophages arrive! She has a strain that eats this food and is resistant to the bacteriophages, and a strain that eats that food and is vulnerable. By arranging the two kinds of food in different patterns on the growth plates, she can imitate communities where vaccinated and unvaccinated people interact or avoid each other to various degrees. She sets up the plates in the lab fridge next to the sophomores' preserved dead frogs and stores the virus in the attached freezer for later. The simulation part of the project is proceeding in parallel; she's got clusters of pixels lighting up in healthy blue and infected green in her virtual neighborhoods.

Contrary to doomsayer expectations, her purchases do not evolve into plagues.

Margaret's danger sense is quiet every time she opens the fridge. Eventually she finishes the simulation part, and it squares with what the bacteria are doing, and she writes down her results and lets herself look at the historical data, and it squares with that too. She writes it all up and goes to the county science fair to present it, and scores well enough to move on to the Massachusetts state-level science fair.

The swarm patrol has a training day on a Saturday, and Margaret and Charity work on giving battle advice to a tactical teleporter.

It's pretty hard. Charity is new to the squad, not the profession, and is pretty far dug in to her local optimum of tactics. She seems to be of the opinion that it's not worth sinking too much effort into this because Margaret's not going to be long-term.

That's pretty reasonable; Margaret focuses on coordinating Caroline and Susan.

Robotics club starts building their ropes-course bot; Margaret works on the control software.

She does well enough at the state science fair to go to the New England regional, but doesn't make the nationals. Now that she can't accidentally get advice she doesn't want, she chats about it with her CDC contact in between reports and prophecies.

He's sympathetic; he didn't get very far in science fairs either.