I PROBABLY READ THE MESSAGE A dozen times. It didn’t become any less scary the more I became familiar with it.

There’s a funny thing about e-mail. Even though it and the rest of the Internet exist somewhere out there in the ether, when something ominous appears on your screen, addressed to you, it feels as though the writer’s there in the room with you. You’ve suffered a home invasion without the duct tape. You want to lock the door, but it’s too late. There’s no place to go.

So someone had been to visit Stefanie’s mother and learned my e-mail address. Someone who was clearly not with the police. And that was no cause for celebration.

It was time to stop kidding myself about whether Stefanie Knight’s death and the $20,000 in her purse were related. Here’s how I figured it played out: Someone had gone to her house expecting to get that money, and when she didn’t have it, she was murdered. Then her killer started looking elsewhere, and showed up on her mother’s doorstep. But she didn’t have it, either. But hey, she said, there was a guy here earlier, said he had her driver’s license, was acting kind of funny. Here’s his name and e-mail address.

I read the note one more time: “Dear Mr. Walker: I’m looking for something I think you got. Don’t do something stupid and give it to some body else.”

Hadn’t I done enough stupid things already tonight? I certainly had no interest in doing any more.

It was the absence of any specific threat that made the note all the more chilling. It was implied. I already knew what this guy would do to someone who didn’t hand over something he wanted. I’d been in that garage. But then again, he didn’t know that I knew Stefanie Knight was dead. Maybe he intended his note to be more matter-of-fact. Maybe I was reading too much into it.

Earth to Zack. Wake the fuck up.

I clicked on “Reply” and wrote: “To Whom It May Concern: Regarding your e-mail about my possessing something you’re looking for, I’m afraid I simply have no idea what you’re talking about.”

I read it over twice, thought it sounded about right. Didn’t protest too much, just stated plainly that he had made some sort of a mistake. An incorrect assumption. A case of mistaken identity, perhaps.

I hit “Send.”

My study door opened. God, did Angie want more money? How much do you need, honey? Ten thou, fifteen?

Paul said, “Are you ready?”

I looked at him blankly. “Ready for what?”

“Jesus, you forgot? We have to be there in ten minutes.”

“What are you talking about?”

“The interview. The parent-teacher thing. It’s been written on the fridge for weeks. At eight. I have to get my ass reamed out by the science teacher, and you’re supposed to be there for it. You and Mom said you were gonna go? And now she’s been called in to work and you have to do it solo.”

The air seemed to be thinning. “I can’t do it,” I said.

Paul did a combination rolling-of-the-eyes, sigh, and shoulder-rolling-head-slumping thing which, if it were an Olympic gymnastic move, would have earned him a 9.9. “You have to go. If you don’t show up for this, I’m dead. Ms. Wilton will kill me. She wants me dead already. She hates me. Maybe if she gets a chance to talk to you, she’ll let up on me a bit. You could tell her to stop giving me a hard time.”

“Maybe you need people giving you a hard time.”

Another eye-roll. “We have to be there in less than ten minutes.”

“Where are your friends?”

“They took off. We’re going to get together later at Andy’s house.”

“You don’t have any homework?”

“Nothing.”

“No science homework?”

“Look, are we going to go or what?”

I swallowed. “I’ll meet you at the front door in two minutes.” Paul vanished and I turned back to the computer. I was about to close the mail program, when the computer beeped.

“You have mail,” it said.

Shit. Was this guy sitting by his computer? The number guy from Hotmail was back. I opened the message. It read:

“Don’t jerk me around, asshole. There can’t be that many Z. Walkers in the phone book.”

And that was it.

“I’m ready!” Paul shouted from the front door. “Let’s roll!” I closed the letter, exited the mail program, and turned off the computer before grabbing my jacket and my cell. I flew past Paul on the way to the car, and he pulled the front door shut.

On the short drive over to the school, Paul said, “What’s with you tonight, anyway?”

“I’m okay. I just have some things on my mind.”

“You just seem, I don’t know, weird.”

“Really, I’m fine. Let’s worry about you and Ms. Winslow.”

“Wilton.”

“Hmm?”

“It’s Ms. Wilton. Not Ms. Winslow. That’ll make a really good impression, Dad, going in and calling her by the wrong name. Like I’m not in enough shit already.”

We said nothing else to each other. The school parking lot was nearly full, and many other parents were walking into the building, some accompanied by their teenage children, some not. But they all assumed a kind of condemned-prisoner gait.

Paul led me down a series of hallways and up a flight of stairs to Room 212, where a small nameplate reading “Ms. J. Wilton” was affixed to the door. “There’s still someone in there,” Paul said, peeking around the corner. “That’s Sheila Metzger’s mom. She’ll kill her when she gets home.”

I was growing weary of Paul’s tales of mothers who wanted to kill their daughters, of teachers who wanted their students dead. “What are we supposed to do?” I whispered so our voices wouldn’t drift from the hall into the classroom. “Just wait around out here?”

“I guess, until Sheila’s mom comes out. Then it’ll be our turn.”

“What kind of trouble are you having with science anyway?”

Paul shrugged. “It’s really stupid. Like I’m really going to need science when I grow up.”

“What do you want to be when you grow up?”

“I dunno.”

“Then how do you know you won’t need science?”

“Because I won’t.”

“Look how interested you’ve become in gardening. That’s science.”

“No, that’s planting and digging. Most of the guys I know getting landscaping jobs for the summer don’t exactly have to wear white lab coats.”

“So why does she hate you, this Ms. Wilton?”

“She just does.”

“Could you be more specific?”

“I think she may have an attitude problem.”

As I leaned up against the brick wall, I thought about the second e-mail. I’d never stopped thinking about it while I tried to go through the motions with Paul and this parent-teacher interview thing. If I’d thought the first note was ominous, the second one was off the scale. This guy was planning to come look for me to get what he wanted. There couldn’t be too many Z. Walkers in the phone book, he’d said. How many Z. Walkers were there, exactly, in the phone book? Suddenly, I had to know.

“Is there a phone book around here?” I asked Paul.

“A phone book? I don’t know. Probably in the office. What do you need a phone book for?”

“I just need to look something up. It’ll only take a minute.”

“You can’t go now. She’s going to call us in any second.”

I peeked around the corner as Paul had done a moment earlier. Ms. Wilton was huddled over one of four student desks pulled together into a single grouping, Sheila’s mother sitting across from her. They were reviewing papers, talking in hushed tones. It looked to me like they weren’t even close to finishing.

“I’ll only be a minute,” I said, and darted off down the hallway to the stairs. I ran back toward the main entrance, past parents waiting outside classroom doors for their appointments. I expected, at any moment, to be told to stop running in the halls. I assumed the office would be near the front of the school, and I was right. Since this was an open-house kind of evening, the door to the office was unlocked and the lights were on. I stood at the counter and called out, “Anyone here?”