“But I told you, it doesn’t travel from cat to cat. So what else is left?”

“Humans.”

She frowned.

“What if this strain really is like malaria?” I continued. “Except with cats instead of mosquitoes? Maybe it just bounces back and forth between felines and people.”

Dr. Rat smiled. “Interesting theory, Kid, but there’s one problem.” She crossed to the cage where the peep cat lay calmly watching us and stuck a finger in through the bars.

“Um, Dr. Rat, I wouldn’t do that…”

She chuckled; the cat was sniffing her finger, its whiskers vibrating. “This cat isn’t violent. It doesn’t bite.”

My hand went to my cheek. “Are you forgetting what it did to my face?”

Dr. Rat gave a snort. “Any cat will attack if you get it mad enough. And anyway that’s a scratch, not a bite.” She turned back to the cat, rubbing its forehead through the wires of the cage. It closed its eyes and began to purr.

“But the cats are important somehow!” I shouted. “I know they are!”

She turned to face me. “The cats? Plural?”

“Oh.” I cleared my throat. “Well, potentially plural.”

Dr. Rat narrowed her eyes. “Cal, is there something you’re not telling me?”

There were lots of things I hadn’t told her. But at that moment a horrible thought crossed my mind…

“Wait a second,” I said. “What if the strain spreads between cats and humans without biting? How would that work?”

Dr. Rat’s suspicious expression didn’t waver, but she answered me. “Well, it could happen in a few ways. Remember toxoplasma?”

“Who could forget toxoplasma? It’s in my brain.”

She nodded. “Mine too. Toxoplasma spores are airborne. Cats leave them in the litter box, then they go up your nose. But that would only work from cat to human, not the other way around. For two-way transmission, you and a cat would have to breathe on each other a lot at short range…”

I remembered something Dr. Rat had said the day before, and my stomach did a back flip. “You mean, if the cat stole your breath?”

She smiled. “Like in those old legends where cats were demons? Yeah. That might work.” A frown crossed her face. “And you know, those old stories date from around the time of the plague.”

“Yeah. Plague.”

Dr. Rat’s eyes widened. My face must have been turning odd colors. “What did I say, Cal?”

I didn’t answer. A small but horrible memory had drifted through my mind, something Lace had said the night before.

“Yeah,” I said softly, “really nice.”

“What’s really nice?” said Dr. Rat.

“I have to go now.”

“What’s wrong, Cal?”

“Nothing.” I stood shakily. “I have to go home is all.”

She raised an eyebrow. “Feeling sick?”

“No, I’m fine. This conversation just reminded me, though… My cat is, um, unwell.”

“Oh.” She frowned. “Nothing serious, I hope.”

I shrugged, dizzy from standing up too fast. My throat was dry. What I was thinking could not be true. “Probably not too serious. You know how cats are.”

The cab ride back to Brooklyn was the most unpleasant twenty dollars I’d ever spent. I stared out the window as we soared across the Williamsburg Bridge, wondering if I’d gone insane. Wondering if Cornelius had really contracted the disease from me.

The old cat had never bitten me, hadn’t even scratched me in the last year.

Airborne, Dr. Rat had said.

That had to be nuts. Diseases transmitted by fluids didn’t just suddenly become airborne. If they did, we’d all die from Ebola, we’d all get rabies from a walk in the woods, we’d all be carrying HIV …

We’d all be vampires.

Of course, diseases change. Evolution never sleeps. But my strain was too well developed to be brand-new. It infected cats, turned its victims into feline-worshippers and carriers, created smarter and saner peeps. A whole raft of adaptations.

And those ancient legends about cats stealing breath—those stories were seven hundred years old. If this strain had been around for seven hundred years, where had it been hiding?

Then I remembered the pale rats below the surface, buried deep until the reservoir had bubbled up beneath the PATH train. Could they have been down there in the darkness for centuries, keeping an ancient strain of the parasite hidden?

And the foul thing I’d smelled but not encountered down there. What did a hidden strain of the parasite have to do with that unseen subterranean creature?

The ride took forever, my sweating palms leaving handprints on the vinyl seats, the sunlight flashing through the struts of the bridge, the taxi meter ticking like a time bomb, and the memory that had struck me in Dr. Rat’s office replaying, Lace’s voice saying again and again: “Except for not having any of my stuff, commuting all the way from Brooklyn, and having your heavy-ass cat lie on me all night. Other than that, it’s been kind of… nice.”

“Yeah. Really nice,” I whispered again.

I picked up a flashlight at the dollar store on the way home.

“Here, kitty, kitty!” I called as the door swung open. “It’s nummy-time.”

For a moment I heard nothing and wondered if Cornelius had somehow figured out that I knew his secret and had escaped my apartment for the wider world. But then he padded out from the bathroom to greet me.

I switched on the flashlight, shining it straight into his eyes…

They flashed bloodred. He blinked at me and cocked his head.

I crumpled to the floor, dropping the flashlight. In addition to all my girlfriends, I’d infected my own cat. How much did that suck? “Oh, Corny.”

He meowed.

After a whole year, how had I not noticed his eyes? Of course, with my night vision, I almost never kept the lights on. Cornelius came to rest his head on my knee and let out a soft meow. I rubbed him, stoking up a good purr.

“How long?” I wondered aloud.

Probably for most of the last year. Cornelius always slept with me on the futon, and I couldn’t count the number of times I’d woken up with him perched on my chest, bathing me in Crunchy Tuna breath. He could have contracted the parasite even before I’d noticed the changes in myself.

Maybe it had been through him that Sarah had been infected. She’d always complained of his bladder-crushing weight in the morning.

Maybe the sex had been irrelevant. Maybe she’d been his peep, not mine. Maybe Lace was already …

I stood up and fed Cornelius, going through the motions on autopilot, fighting off panic. She’d only spent one night here, after all. And even if she’d been infected, it wouldn’t be as bad as Sarah. This was an early diagnosis. I just had to get her into treatment as soon as possible.

Of course, getting her into treatment meant going to the Night Watch and admitting that I’d committed a Major Revelation Incident. And telling them everything I’d seen out in Brooklyn, and that the Mayor’s office was covering something up. And trusting them with Lace’s life, when I didn’t even trust them to use the phone book anymore.

I began to realize just how badly everything was about to crumble. The Night Watch had been corrupted and the parasite had gone airborne, helped along by Morgan Ryder—a new Typhoid Mary, with the added bonus of feline familiars.

Even if Lace wasn’t already infected, I had to warn her. No matter how nonviolent Patricia and Joseph Moore might seem at the moment, someone had eaten the guy in 701 and turned his guts into graffiti.

I remembered the motivational computer simulations Dr. Rat had shown in Peep Hunting 101—showing how we were helping to save the world. On their way to being epidemics, diseases reach something called critical mass, the point at which chaos begins to feed upon itself—roving peeps in the streets, garbagemen afraid to go to work, garbage piling up, rats breeding and biting—more peeps. Except that this strain would include nervous people getting cats to save them from the rats, and the cats making more peeps…