“Oh, good. Because I was really worried about wolves.” She turned to me. “So, it’s a parasite? Like a tick or something?”

“Yeah. It’s not like a flu or the common cold. It’s an animal.”

“What the hell kind of animal?”

“Sort of like a tapeworm. It starts off as a tiny spore, but it grows big, taking over your whole body. It changes your muscles, your senses, and most of all, your brain. You become a crazed killer, an animal.”

“Wow, that is really freaky and disgusting, Cal,” she said, cinching her bathrobe tighter.

Tell me about it, I thought, but didn’t say anything. I might have promised not to lie to her, but my personal medical history was not her business.

“So,” Lace said, “does this disease have a name?”

I swallowed, thinking about the various things it had been called over the centuries—vampirism, lycanthropy, zombification, demonic possession. But none of those old words was going to make this any easier for Lace to deal with.

“Technically, the parasite is known as Echinococcus cannibillus. But seeing as how that takes too long to say, we usually just call it ‘the parasite.’ People with the disease are ‘parasite-positives,’ but we mostly say ‘peeps,’ for short.”

“Peeps. Cute.” She looked at me, frowning. “So who’s this we you’re talking about anyway? You’re not really with the city, are you? You’re some sort of Homeland Security guy or something.”

“No, I do work for the city, like I said. The federal government doesn’t know about this.”

“What? You mean there’s some insane disease spreading and the government doesn’t even know about it? That’s crazy!”

I sighed, beginning to wonder if this had been a really bad idea. Lace didn’t even understand the basics yet—all I’d managed to do was freak her out. The Shrink employed a whole department of psych specialists to break the news to new carriers like me; they had a library full of musty but impressive books and a spanking new lab full of blinking lights and creepy specimens. All I was doing was haphazardly answering questions, strictly amateur hour.

I pulled a chair over and sat down in front of her. “I’m not explaining this right, Lace. This isn’t an acute situation. It’s chronic.”

“Meaning what?”

“That this disease is ancient. It’s been part of human biology and culture for a long time. It almost destroyed Europe in the fourteenth century.”

“Hang on. You said this wasn’t the plague.”

“It isn’t, but bubonic plague was a side effect. In the 1300s, the parasite began to spread from humans to rats, which had just arrived from Asia. But it didn’t reach optimum virulence with rodents for a few decades, so it mostly just killed them. As the rats died, the fleas that carried plague jumped over to human hosts.”

“Okay. Excuse me, but what?”

“Oh, right. Sorry, got ahead of myself,” I said, knocking my head with my fists. The last six months had been one big crash course in parasitology for me; I’d almost forgotten that most people didn’t spend days thinking about final hosts, immune responses, or optimum virulence.

I took a deep breath. “Okay, let me start over. The parasite goes way back, to before civilization even. The people I work for, the Night Watch, also go way back. We existed before the United States did. It’s our job to protect the city from the disease.”

“By doing what? Sticking rats in spaghetti strainers?”

Release me! squeaked PNS.

“No. By finding people with the parasite and treating them. And by destroying their broods—um, I mean, killing any rats who carry the disease.”

She shook her head. “It doesn’t make sense, Cal. Why keep it a secret? Aren’t you Health Department guys supposed to educate people about diseases? Not lie to them?”

I chewed my lip. “There’s no point in making it public, Lace. The disease is very rare; there’s only a serious outbreak every few decades. Nobody tries to get bitten by a rat, after all.”

“Hmm. I guess not. But still, this secrecy thing seems like a bad idea.”

“Well, the Night Watch up in Boston once tried what you’re talking about—a program of education to keep the citizens on the lookout for possible symptoms. They wound up with nonstop accusations of witchcraft, a handful of seventeen-year-olds claiming they’d had sex with the devil, and a lot of innocent bystanders getting barbecued. It took about a hundred years for things to settle down again.”

Lace raised an eyebrow. “Yeah, we did that play in high school. But wasn’t that a long time ago? Before science and stuff?”

I looked her in the eye. “Most people don’t know jack about science. They don’t believe in evolution because it makes them uncomfortable. Or they think AIDS is a curse sent down from God. How do you think those people would deal with the parasite?”

“Yeah, well, people are stupid. But you wouldn’t keep AIDS a secret, would you?”

“No, but the parasite is different. It’s special.”

“How?”

I paused. This was the tricky part. In my own debriefing, the Night Watch psychs had presented all the science stuff for hours before talking about the legends, and it had been a solid week before they’d uttered the V-word.

“Well, some fears go farther back than science, deeper than rational thought. You can find peep legends in almost every culture on the globe; certain of the parasite’s symptoms lend themselves to scary stories. If we ever get a major outbreak of this, there will be hell to pay.”

“Certain symptoms? Like what?”

“Think about it, Lace. Peeps are light-fearing, disease-carrying cannibals who revel in blood.”

As the words left my mouth, I realized I’d said too much too quickly.

She snorted. “Cal, are we talking about vampires?”

As I struggled to find the right words, her amused expression faded.

“Cal, you are not talking about vampires.” She leaned closer. “Tell me. You’re not supposed to lie to me!”

I sighed. “Yeah, peeps are vampires. Or zombies in Haiti, or tengu in Japan, or nian in China. But like I said, we prefer the term parasite-positive.”

“Oh. Vampires,” Lace said softly, looking away. She shook her head, and I thought for a moment that the slender thread of her trust had broken. But then I realized that her gaze was directed at the wall where the words written in blood many months before showed through.

Lace’s shoulders slumped in defeat, and she drew the robe tightly around her. “I still don’t see why you have to lie about it.”

I sighed again. “Okay, imagine if people heard that vampires were real. What would they do?”

“I don’t know. Freak out?”

“Some would. And some wouldn’t believe it, and some would go see for themselves,” I said. “We figure at least a thousand amateurs would head down into the bowels of New York to look for adventure and mystery, and they would become human germ elevators. Your building is just one acute case. There are dozens of rat reservoirs full of the parasite down there, enough to infect everyone who takes the time to look for them.”

I stood up and started to move around the room, recalling all the motivational classes in Peep Hunting 101.

“The disease sits under us like a burned-down camp-fire, Lace, and all it needs is for a few idiots to start stirring the embers. Peeps were deadly enough to terrorize people back in tiny, far-flung villages. Imagine massive outbreaks in a modern-day city, with millions of people piled on top of one another, close enough to sink their teeth into any passing stranger!”

Lace raised her hands in surrender. “Dude, I already promised. I’m not going to tell anyone, unless you lie to me.”

I took a deep breath, then sat down. Maybe this was going better than I’d thought. “I’ll be handling this personally. All you have to do is sit tight.”