He held up his hands in surrender. “Okay, okay. Well, we can start by tracking down the null, right? There are how many of you?”

“That I know of? A handful,” I said. I started walking again. “But who knows how many there are total. The theory is that there are some nulls who never find out what they are.” I explained the difficulty in discovering new nulls. “If the null lives in a city with a low Old World population, they might live and die without ever knowing. There’s another argument that says that doesn’t happen, because nulls evolved to be born near Old World populations, but that’s all theoretical.”

“How many do you know about?”

I counted in my head. “Six. But we’re all really spread out, geographically. There’s one in New York, two in Europe, one in Japan, one in Russia, and me. That’s it.” From the corner of my eye, I saw his eyebrows furrow and his mouth open. I held up both palms in a stop gesture. “No, I have no idea why. We just seem to be born spread out like that. The Old World doesn’t spend a lot of time trying to solve those kinds of questions—at least not with modern scientific methods—so nobody has many answers.” To her credit, Olivia had at least tried to make connections between the nulls, spending most of one summer working on an online network between us. I’d corresponded with a couple of people at one point, the ones who spoke good English, but I hadn’t heard from anyone in more than eight months. Since she’d died.

“Well, can we find those nulls? Find out where they were the other night?”

“Yeah, sure,” I said. “But do you really want to spend time trying to track down international alibis when there could theoretically be unknown nulls right here in the US?”

He looked unhappy. “It’s a cop thing. I have to cover all the bases, even the unlikeliest ones. Can you get me a list of names and phone numbers?”

“I only have e-mail addresses. But it’d be better coming from me.”

He thought that over for a moment. “Okay.” He shook his head. “Man, this stuff is weird.”

“Tell me about it.”

We were back at Cruz’s car. Cruz checked his watch. “Scarlett, look...I have to get to the airport, solidify my alibi for this afternoon. Could you maybe find your own way home?”

Molly’s place was only a couple of miles north, but it was still annoying. “Fine,” I grumbled.

“Great,” he said, undeterred. “I’ll come and get you when I’m done with my shift.”

“Call first. Where are we going?”

“To cover some more bases. I want you to think about places where these Old World...um...people, hang out. Like that bar. And I want to show their pictures around, see if we can ID anybody. Then we’ll go see the vampire boss after dark.”

I groaned. “That’s not going to go over well.”

He shrugged, unrelenting. “That’s how it is sometimes.”

I swallowed another lecture about taking vampires seriously and being respectful—scratch that, afraid—of Dashiell. Maybe later.

I considered walking back to Molly’s, but ended up splurging on an overpriced cab. As soon as I got there, though, I realized there wasn’t anything I needed to be doing. I toyed with the idea of tackling my laundry or starting to work on the search for a new assistant, but I didn’t have the energy for either. Instead, I decided to wake up Molly. If she was going to question me or spy on me or whatever, I wanted to get it over with.

As I walked into her room, Molly gasped, her eyes flying open. Sometimes it’s like that. “Hey,” she said, running a hand through the tangles in her red hair. Vampire hair and fingernails grow. I don’t know why the magic works like that, but it does. Which is good for Molly, because she gets bored with her hair every three months or so. “You’re home! Ooh, it’s only three thirty, that’s so awesome. Want to go shopping? I was thinking I needed a new laptop bag.”

She seemed back to her usual peppy self, and I let out a breath I didn’t know I had been holding. I decided I didn’t really want to spend the day brooding about the possibility of another null being in town. “That sounds fine, if that’s what you want to do.”

“Really?” she squealed. “Let me just get dressed.” I had to stay in the room in order for this to happen, so I politely turned my back. She thinks that’s hilarious and told me so again.

I’ve seen a couple of reality TV shows where people—usually couples—are tied together and forced to stay within a few feet of each other. In real life, without the additional help of a rope (I’ve considered it, but even in LA, I think it’d look too weird), this is surprisingly hard to keep up. It’s so easy to forget and go off to the bathroom or wander a few feet away to look at something or answer your cell phone. By now, though, Molly and I had it down to an art form. We only screwed up once, early in our relationship, when we got separated in a crowd at the farmers’ market. Luckily, we were indoors, so when she collapsed, we just told everybody that she’d fainted. Close call.

We went to Westside Pavilion, and I followed Molly around Nordstrom’s for a while, ignoring her pleas to pick out a new wardrobe for me. Molly thinks my T-shirt-and-jeans look is gauche and trashy, and is constantly trying to use me as her own personal Barbie doll. I once pointed out that she wears T-shirts all the time, but she airily told me that her shirts and jeans were expensive, so it was okay. I don’t think there’s anything okay about paying $200 for jeans, but I’m crazy like that.