“So does this building have the plague or something?”

Rats and plague did go together. Would Lace believe that one? My mind began to race.

“No, dude,” Lace said firmly, rising to her feet and putting a finger in my face. “Don’t sit there making shit up. Tell me the truth.”

“Uh … I can’t.”

“You’re trying to hide this? That’s nuts!”

I stood and put my hands on her shoulders. “Listen, I can’t say anything. Except that it’s very important that you don’t tell anyone about what’s down there.”

“Why the hell would I keep quiet? There’s a swimming pool full of rats in my basement!”

“You just have to trust me.”

“Trust you? Screw that!” She set her jaw, and her voice rose. “There’s a disease that makes people write on the walls in blood spreading through my building, and I’m supposed to keep it a secret?”

“Um, yes?”

“Well, listen to this, then, Cal. You think this should be a secret? Wait till I tell Manny what I saw down there, and Max and Freddie and everyone else in the building, and the New York Times and the Post and Daily News, for that matter. It won’t be very secret then, will it?”

I tried to pull off a shrug. “No. Then it’ll just be a building in New York City with rats in the basement.”

“Not with that thing on my wall.”

I swallowed and had to admit she had something there. With Morgan’s gristle graffiti added into the mix, the NYPD would have a reason to reopen apartment 701 ’s missing persons case, which might lead them in all sorts of uncomfortable directions. The Night Watch was usually pretty good at making investigations go away, but this one would be tricky.

Which meant I was supposed to call the Shrink right now and tell her what had happened. But the problem with that was, I already knew what she’d tell me to do. Lace would have to disappear forever. All because she’d tried to help me.

I stood there in silence, paralyzed.

“I just want the truth,” Lace said softly. She sat down heavily on a weight bench, as if her nervous energy had run out.

“It’s really complicated, Lace.”

“Yeah, well, it’s pretty simple for me—I live here, Cal. Something really hideous is going on under our feet, and something insane happened right in my living room. It’s starting to freak me out.”

On those last words, her voice broke.

She could smell it now. With all she’d seen, Lace could feel the capital-N Nature bubbling up from below—not the fuzzy Nature at the petting zoo, or even the deadly but noble kind on the Nature Channel. This was the appalling, nasty, real-world version, snails’ eyes getting eaten by trematodes; hookworms living inside a billion human beings, sucking at their guts; parasites controlling your mind and body and turning you into their personal breeding ground.

I sat down next to her. “Listen, I understand you’re scared. But knowing the truth won’t make it any better. The truth sucks.”

“Maybe. But it’s still the truth. All you’ve done is lie since you met me, Cal.”

I blinked. She didn’t. “Yeah,” I said. “But—”

“But what?”

At that moment, I knew what I really wanted. After six months of the natural world getting steadily more horrible, of my own body turning against me, I was just as scared as Lace. I needed someone to share that fear with, someone to cling to.

And I wanted it to be her.

“Maybe I can explain some of it.” I breathed out slowly, a shudder going through me. “But you’d have to promise not to tell anyone else. This isn’t some journalism class project, okay? This is deadly serious. It has to stay secret.”

Lace thought for a few seconds. “Okay.” She raised a finger in warning. “As long as you don’t lie to me. Ever.”

I swallowed. She’d agreed way too fast. How could I believe her? She was studying to be a reporter, after all. Of course, my only other choice was the phone call that would make her disappear.

I stared into her face, trying to divine the truth of her promise, which probably wasn’t the best idea. Her brown eyes were still wide with shock, her breathing still hard. My whole awareness focused itself upon her, a tangle of hyped-up senses drinking her in.

My guess is the parasite inside me made the choice. Partly anyway.

“Okay. Deal.” I put out my hand. As Lace shook it, a strange thing happened: Instead of shame, I felt relief. After keeping this secret from the whole world for half a year, I was finally telling someone. It was like kicking my boots off at the end of a really long day.

Lace didn’t let go of my hand, her grip strengthening as she said, “But you can’t lie to me.”

“I won’t.” My mind was clearing, beginning to work logically for the first time since the earth had started to tremble, and I realized what I had to do next. “But before I tell you, I have to sort out a couple of things.”

Lace narrowed her eyes. “Like what?”

“I need to secure the basement: Chain up that big door behind the wall and lock that locker.” I could leave my duffel bag downstairs, I realized. The rats wouldn’t steal it, and I’d need the equipment right where it was the next time I went down. But there was one last thing I had to get before we left. “Um, do you have a flashlight? Or a lighter on you?”

“Yeah, I’ve got a lighter. But Cal, tell me you’re not going down those stairs again.”

“Just for a second.”

“What the hell for?”

I looked into her brown eyes, wide with rekindled fear, but if Lace wanted to know the truth, it was time she found out how nasty it could be.

“Well, since we’re already down here and everything, I really should catch a rat.”

“Okay, I’m tracking a disease. That part of my story was true.”

“No kidding. I mean, rats? Madness? Bodily fluids? What else could it be?”

“Oh, right. Nothing, I guess.”

We were up in Lace’s apartment. She was drinking chamomile tea and staring out at the river; I was cleaning poisonous peanut butter out of my boot treads, hoping the task would distract me from the fact that Lace was wearing a bathrobe. A rat called Possible New Strain was sitting under a spaghetti strainer held down with a pile of journalism textbooks, saying rude things in rat-speak.

I’d caught PNS at the top of the stairs, snatching him up in a rubber-gloved hand as he sniffed one of Lace’s peanutty footprints.

Lace cleared her throat. “So, is this a terrorist attack or something? Or a genetic engineering thing that went wrong?”

“No. It’s just a disease. The regular kind, but secret.”

“Okay.” She didn’t sound convinced. “So how do I avoid getting it?”

“Well, you can be exposed through unprotected sex, or if someone bites you and draws blood.”

“Bites you?”

“Yeah. It’s like rabies. It makes its hosts want to bite other animals.”

“As in ‘So pretty I had to eat him’?”

“Exactly. Cannibalism is also a symptom.”

“That’s a symptom?” She shuddered and took a sip. “So what’s with all the rats?”

“At Health and Mental they call rats ‘germ elevators,’ because they bring germs that are down in the sewers up to where people live, like this high-rise. A rat bite is probably how Morgan, or someone else up here, got infected in the first place.”

I saw another shudder pass through the shoulders of her bathrobe. Lace had taken a shower while I’d called Manny and told him to lock up the health club. Her face looked pink from a hard scrubbing, and her wet hair was still giving off curls of steam. I turned my attention back to my boots.

At the mention of rat bites, she lifted her feet up from the floor and tucked them under her on the chair. “So, sex and rats. Anything else I should worry about?”

“Well, we think there used to be a strain that infected wolves, based on certain historical … evidence.” I decided not to mention the bigger things that Chip was worried about, or whatever had made the basement tremble, and I cleared my throat. “But as far as we know, wolves are too small a population to support the parasite these days. So, you’re in luck there.”