Corn is vulnerable to blight by an airborne fungus called Ustilago maydis, commonly referred to as corn smut. Hundreds of millions of dollars are lost every year because of it. When Isaac Peaches worked as a genome engineer, one of his directives was to find a way to stop its spread. He tried a thousand different modifications that might create stronger, more resistant strains before finally getting the idea of adding something to the mix: a killer protein. Instead of going on the defense, he would take the offense, an act so very unlike him that he surprised himself. This symbiotic strain of corn he designed had a built-in fungus, KP4, that ate other fungi. The idea was to infect the infection.

This is what he tells Dr. Johnson to try as he leaves the hospital.

“But KP4 is a toxin,” she says, and he says, “So’s chemo. Just try a low-dose version and see if you get any results.” He’s sure she will. But stopping the spread will also require contact tracing and isolation. Seattle is going to be in the news as a hot zone for the next few weeks at least. The good news is, the infection won’t spread except sparingly, due to environmental factors. There are other areas of the world, after all, where omnimetal strikes have been discovered, so the spores must be there as well. But it’s only here—so far, anyway—that they’ve flourished. It must be because of the funk. The mossy, earthworm-y funk of the Sound and the Olympics. In a normal year, it gets over one hundred inches of rain, the wettest geography in the country. It’s its own special aquarium, the perfect incubator.

The doctor has more questions, but he can’t linger because Director Ricketts is waiting for him on the helipad. The morning shift at the DOD facility discovered the lab compromised, a guard handcuffed to the docks, and the girl and her parents escaped. Teams are assembling to scour the coastline by boat and plane, but the fog stewing through the Sound isn’t going to make it easy.

Director Ricketts blames Isaac. And he will be punished accordingly. But first they have work to do. When he was in the chapel, his SPLICER program translated the fungal pattern as a circular key chain, the necrotic zone of which is growing more rapidly and expansively with each new infection. Every patient had a slightly different code, but they all linked back to a parent generation from which the mycelium network began. It wasn’t that different from DNA testing, and the original source, the master infection, was a man named Albus Crotter, a serial killer who liked to leave his mark on his victims. The same holds true now.