“Any reason they were just outside the car without a lead on?”

Now Nathan spoke up. “I’m sorry, Officer. They were whining, and my girlfriend was asleep, and I took them out so that she wouldn’t have to. I never even thought to grab their leashes.”

“This is state land. It’s against local ordinance for dogs to be in the fields without leads.” The flashlight beam switched to Nathan’s face, finally allowing me to see the officer on the other side. He was a big man of African-American descent, thick around the middle, with a face that seemed inclined to be gentle, even as he was interrogating Nathan about walking the dogs. “Did you see any wildlife while you were out there?”

It smacked of a question that had a right answer and a wrong answer. I bit my lip as I waited to see which one Nathan was going to offer.

“I think we startled a duck,” he said. “It flew away when Minnie got close to it, and the dogs did their business—urine only, I had bags in case they decided to poop—and we got back into the car. My girlfriend was awake by that point, I told her what I’d done, and we started to get back on the road. That’s when you pulled us over.”

The flashlight beam switched back to my face, making my eyes water. I squinted, resisting the urge to raise a hand against the glare. Looking inoffensive was important when dealing with the police, never more than right now. “Miss, is this true?”

“I can’t say about the duck, because I was in the car, but all the rest is true as far as I know,” I said meekly. “I’m really sorry. I would have told him to put the leashes on if I’d been awake.”

“Miss, why is there blood on your shirt?”

The question was asked in the same mild, almost innocuous tone as the questions about the dogs, and for a moment, I didn’t realize how dangerous it was. The moment passed quickly. I swallowed hard before holding up my injured arm, showing him the bandage wrapped around my wrist. “I was making dinner, and I slipped,” I said. “I cut myself pretty bad, and I didn’t have a clean shirt, so we’re heading back to my place to get me a change of clothes.” It seemed odd to avoid using Nathan’s name, but he hadn’t used mine, and I had to assume that there was a reason for that. Maybe he just didn’t want to risk the cop guessing who we were… but wouldn’t the officer have run Nathan’s plates before he got out of his squad car? Didn’t he already know?

There were too many variables. I was drowning in them.

“I see.” The flashlight moved away from my eyes to my bandaged wrist, and hovered there as the officer considered my words. Finally, he asked, “Are you being held against your will?”

“What? No!” I was so startled by the question that I forgot to moderate my response. I wound up half squawking at the cop, my eyes going wide and round with surprise.

Maybe that was the right way to react. The flashlight finally pointed upward at the ceiling of the cab, where it illuminated the car without blinding anyone. “I don’t know if you were aware, but I just got the call that we’re closing down the bridge,” said the officer. “It seems there’s been some sort of outbreak in San Francisco, and we’re trying to contain it before it can spread to the rest of the Bay Area. You kids wouldn’t know anything about that, would you?”

“No, Officer,” said Nathan.

I didn’t trust my voice, and so I just shook my head, hoping that the policeman would take my silence as a sign of fear, and not a sign of guilt.

“You look like good kids, but it’s not safe out here,” he said. “Wherever it is you’re going, you want to keep going until you get there, you hear me? Don’t stop again, no matter how bad your dogs need to pee.”

“Yes, sir,” said Nathan. “Thank you.”

“I’m letting you off with a warning this time. Get your girl home.” Then the flashlight was turned away, and the officer was walking back down the shoulder toward his car. Nathan and I raised our eyes to watch him go, tracking his reflection as it got smaller and smaller, until he finally climbed into his squad car. The lights flashed once as he restarted the engine, and then he pulled out onto the highway and was gone.

Nathan groaned, leaning forward to rest his forehead against the wheel for a moment. I blinked at him, alarmed.

“Nathan?”

“This is how everything falls apart, Sal,” he said, voice slightly muffled by his position. “This is where everything breaks down. That man should have hauled us in—between the blood and the bridge shutting down, we’re too suspicious to be allowed to roam free. But he didn’t, because we looked like ‘nice kids,’ and you’re a pretty girl with big, sad eyes, and he didn’t want to do that to us. We looked too innocent.”

“That’s… bad?” I asked blankly.

“No one is innocent when you’re talking about infection, whether it’s viral or parasitic.” Nathan raised his head and started the engine again. “We’re not carrying SymboGen implants on the verge of going rogue, but we could be. There’s no way to look at a person and know. So if we were carriers, and if the goal were to shut down the sleepwalker plague in San Francisco, our friendly neighborhood state trooper would have just ruined everything.”

“Everyone’s a carrier,” I said. “You’re being really hard on him. He let us go.”

“Everyone’s a potential carrier. There will always be outliers, like you, but it seems like most sleepwalkers are triggered by getting near another sleepwalker. The pheromone tags put off by the worms in their new state excite and agitate the worms that are still in a resting phase. The change isn’t instant unless the second worm was already in the process of attempting to colonize the brain of their host—it takes time to chew and slither your way through a human body—but it starts with that pheromone tag. That’s why Sherman could form a mob by dropping one or two individuals in key neighborhoods. That’s why Mom was so worried about us going out in public. There’s no telling how many people are already out there, putting off the pheromone tags that say ‘it’s time to move,’ and haven’t yet started showing symptoms.”