He was slightly out of breath. "I'll be fine. The images were-confusing. I'm not sure if anything that I said made sense."

"It did." I folded my arms. "We're back to our very first premise-that Cassandra killed Sebastian. We don't know why yet, or even how, but we at least know that it happened here. Then she transported him to the alley, posed him-or maybe she got someone else to do it. That's why his aura was so faint, and the crime scene was so clean." I gestured to the living room. "This was the real crime scene. This is where Sebastian's life was actually snuffed out."

"But we still can't explain the vampire's injuries," Derrick said. "Cassandra didn't have the power to inflict that kind of neurological damage, right? I mean, if she did, don't you think she would have made short work of those Vailoid demons?"

"We don't even know what kind of demon-" The word came out before I could stop it. I stared at Mia in horror.

She didn't react. Her eyes scraped the ground, but she said nothing.

"Mia-" I began.

"Don't bother." She shook her head. "I kind of figured anyway. I mean, nothing else in my life is true, or real. Why should my aunt be any different?"

"She loved you, Mia."

"She wasn't even human."

"Neither are we," Derrick said softly.

Mia stared at him.

"He's right," I said. "Technically, Derrick and I are part-demon, too. A lot of people are." You probably are, I thought, but this time I kept myself from saying it. I could hear Derrick's speech about morality, about shades of gray. "Not all demons are evil," I said slowly. "It's complicated."

She didn't say anything.

"I'm-ah-going to go check out the kitchen," Derrick said. "You two can chill out in here for a while."

He disappeared into the next room.

Mia sat down slowly on the couch.

"Are you all right?" I cursed myself. "Sorry. Dumb question. "

She shrugged. "You know, I've lived in this house for as long as I can remember. Seems like-God-forever, I guess."

"I know the feeling," I said.

"Yeah. Sure." Mia lay down on the couch, drawing her knees up to her chest. "You probably just think I'm a whiny brat with nothing to complain about."

"Are you kidding?" I shook my head. "Mia, you've got to be the strongest person I've ever met. I mean, you've been through so much already, and you're still just taking it as it comes. I totally respect you for that."

She laughed softly. "I don't feel like I'm taking anything in a good way right now. Seems more like I'm freaking."

"That's perfectly natural."

"You my counselor now?"

"Mia." I raised my hands. "I don't know how to make this better. There's probably nothing I can say that will help, but I really am trying."

"I know." She looked away. "You and Derrick are both great. I don't even know why you're helping me so much. It's not like I deserve it."

"What are you talking about?"

"Oh, come on." She was staring at the wall-unable to look me in the eye. "The minute I showed up in that parking lot, all hell broke loose. Your lives have pretty much been shit-"

"Language," I said, although I knew it was useless.

She sighed. "Okay, your lives have been extra-spicy since I appeared. I mean, have you even slept at all for the past couple of days?"

God, she didn't know the half of it. I hadn't even told her about the vampires yet, or explained the fact that her powers-her immense powers, if I was right-were probably being held in abeyance by some kind of mystical retrovirus. Something told me that I wasn't going to be sleeping at all for the next week.

"I can manage," I said, shrugging. "It's you I'm worried about. You're a teenager, and your body-"

"Oh, lord, not the 'your body is a wonderland' speech. I know all about puberty, Tess."

"I'm sorry." It sounded like the stupidest condolence possible. Grief was a gaping hole in your life that no flowers or sympathy cards could fill. It was a mass of bloody scar tissue that people noticed, but politely declined to mention.

"It's no big deal anymore," Mia replied. "I'm used to death."

"Nobody ever gets used to it."

Finally, she looked me in the eyes. "I loved my aunt," she said. "She could be a real bitch-and yeah, I know, that's shitty language. But she could."

"I'll bet," I said.

"Yeah, she could drive me crazy. But she was the only parent I had left, and now she's gone. Completely gone." Her voice cracked. "And that's fucking stupid, and I don't understand it, and it sucks. She's never going to piss me off by calling me on my cell phone again. She's never going to come into my room without knocking, or make me potato salad, or warn me about boys. And she'll never sit on this couch again watching Home and Garden Television."

I smiled.

"It sucks." Mia seemed to collapse into herself. "It sucks that we die. And I hate it, and I even hate myself a little, but I can't just sit here and freak out. Even if I wanted to, we don't have the time, because crazy people are after us."

"Crazy demons," Derrick corrected, walking out of the kitchen. "Everything seems fine in there. Untouched. And if there were any demons here, I'm sure they've heard us all talking now, so there's no use trying to be stealthy."

"We might as well check out the bedrooms, then," I said.

I went upstairs, with Mia close behind. My mind was racing. I kept forming explanations for her, then deleting them and starting all over again.

We came to a hallway with three evenly spaced doors. The carpeting was soft under my shoes-a comforting shade of beige-and the stairs even had one of those plastic runners.

This was definitely an older woman's house.

Together, we walked into Cassandra's room. It was fairly spacious, with a big, four-poster bed in the middle, resplendent with pillows, shams, and a down quilt.

"Now, here's a woman who knows how to make a bed," I said.

"Knew," Mia corrected softly.

I looked at her. "Sorry."

There was a Tiffany lamp on the nightstand, and an oak dresser in the far corner. Everything was clean and tasteful. No dust anywhere. Cassandra had obviously been a Type A personality.

I got down on my hands and knees and looked under the bed-not an easy feat, since my ribs still ached from that last encounter with the Vailoid demon. But there was nothing there. Just darkness and dust.

"Mia, why don't you grab whatever you can carry from your room? Then we'll get out of here before the company arrives."

"Okay. I'm grabbing my flatiron, then."

Then she walked away, leaving me alone in Cassandra's bedroom.

I surveyed it once more-the comfortable furnishings, the cozy bed, the walk-in closet full of sensible shoes. Everything about Cassandra's life had seemed dull on the surface, but who knew what she was really up to? Why would a powerful demon sacrifice her life to save a human girl? I felt like I was shaking a box full of bones and rubies, trying to make something fit, trying to augur something. There was blood. There was magic. And now there was an empty house.

Mia walked back into the bedroom, and I tried to refocus. She had a knapsack slung over her shoulder-it was bulging.

"I've got everything I need," she said. "If I forgot something, we can always come back."

I didn't say anything.

"Tess-we can come back, right?"

"Of course." I tried to keep the fear out of my eyes. "But for now, I think it's time to go. We'll stop by the all-night grocery and pick up some stuff on our way back to the lab. Mia, do you have any dietary restrictions that I should know about?"

Derrick stared at me, open mouthed.

"What? It's a valid question. And no, I am not channeling my mother."

"I'm fine, Tess," she said, smiling slightly. "Whatever you get is fine. I'm not all that hungry anyway."

"All right. Let's go, then."

I felt a bit more relaxed now. Mia lagged behind, but I didn't tell her to keep up. She was going to have to say good-bye to this house in her own way. I couldn't rush her through that, and I couldn't do it for her.

We came to the living room again. "Is there anything you'd like to take from here?" I asked.

Mia shook her head. "It's all just stuff, right?"

Sometimes the clarity of a teenager was amazing. I nodded.

"Yeah, I guess it is."

"Oh, wait-my green tank top." Mia reached into the couch cushions and pulled up a wrinkled shirt-a very small shirt, I noticed critically.

Then I saw it.

"Tess?" Derrick saw me staring intensely at the couch.

"Nobody move," I said. I reached into my purse, where I always kept a few forensic supplies, for occasions exactly like this. I pulled out a tape-lift and knelt in front of the couch. Lying on the black cushion, like a gleaming gold coin, was a single yellow thread. It gleamed against the dark upholstery.

I lifted the fiber and examined it beneath the tape. Visually, it matched the fiber that we'd recovered from the Vailoid demon's neck wound. I was willing to bet that it was Muga silk-just as Cindee had described.

But where had it come from?

My mind was racing. Had it been there the whole time, and I just hadn't noticed it until now?

Or had it rubbed off Mia's clothing? And if that was the case, then what was she doing carrying the fiber around? Where had it originated?

"Tess, it looks like your brain is about to explode." Derrick put a hand on my shoulder. I realized then that I hadn't told him about the silk fiber. I'd forgotten about it until this very moment.

I was about to answer when my cell phone rang.

Shit. I didn't want to take the call, but it might be Selena. I flipped open the phone and said, in that much-too-loud voice that usually comes out when you answer a cell phone: "Yes? Hello?"

I was surprised to hear the voice of Ben Foster, our DNA lab tech, on the other end of the line. He was the last person I'd expect to be calling me. "Tess? This is Ben calling from Serology."

"Hi, Ben-what's going on?"

"Well, we just got the results back from that blood sample-you know, the one you recovered from SemTec Laboratories?"

My heart skipped a beat. "Yes, I know the one."

"I would have told Selena first, but I can't seem to find her anywhere-and Marcus is away on assignment. He hasn't been answering his phone all day. The paperwork that I have might be old, but it lists you as the secondary investigator on this case." There was a pause. "Is that still accurate?"

I breathed a silent prayer to whatever deity might be listening. I had no idea how my namehad gotten recorded as the secondary for that case, since I'd been breaking about twelve CORE rules just entering the lab in the first place. But somehow I was on a piece of paper somewhere. By a sheer clerical error, I was still in the loop.

"No-ah-that's right," I said. "You can tell me the results."

"You're not going to like them."

I exhaled. "Just tell me, Ben."

"Well, we compared that sample to the DNA that we took from Mia Polanski, and it's a match."

I frowned. "So the blood on the slide was Mia's?"

"That's not all. We detected an unusually elevated hematocrit volume. Nearly 0.9. The normal hematocrit volume for a healthy human is somewhere around 0.52. You see, hematocrit is the proportion of blood volume that's occupied by red blood cells. Usually, we just look at hemoglobin and mean cell volume, but-"

"Ben, that's not important!" I snapped. "Just tell me what it means. Why is the red blood cell count so high?"

"I was about to explain it," he sniffed.

I closed my eyes. "I'm sorry. Please continue."

"When we saw the hematocrit count, we did an ABO typing, along with a detailed RFLP analysis of Mia's DNA. That's why it took so long for me to get back to you-we had to probe her DNA using the old electrophoresis method, which is slower, but produces a more detailed result. With the Restriction Fragment Length Polymerase Test, you have to lay out the sample on an electrically conducive gel tract-"

"Ben."

He sighed. I was completely disrupting the satisfaction he'd normally derive from explaining a complex technical procedure. "Her blood type was AB positive, but the RH factor was all messed up. So we tested for viral plasmids."

I could feel a sense of dread slowly moving through my chest and into my throat. I swallowed. "What kinds of plasmids?"