Then he added casually, like he was talking about how to fix a toaster, “Besides, a nuclear device can’t do much damage in the vacuum of space. There’s nothing to carry the shock wave.”

“So this brainiac on TV is just full of shit?”

“Don’t use that language, Cassie,” he chided me. “He’s entitled to his opinion, but that’s all it is. An opinion.”

“But what if he’s right? What if that thing up there is their version of a Death Star?”

“Travel halfway across the universe just to blow us up?” He patted my leg and smiled. Mom turned up the kitchen TV. He pushed the volume in the family room to twenty-seven.

“Okay, but what about an intergalactic Mongol horde, like he was talking about?” I demanded. “Maybe they’ve come to conquer us, shove us into reservations, enslave us…”

“Cassie,” he said. “Simply because something could happen doesn’t mean it will happen. Anyway, it’s all just speculation. This guy’s. Mine. Nobody knows why they’re here. Isn’t it just as likely they’ve come all this way to save us?”

Four months after saying those words, my father was dead.

He was wrong about the Others. And I was wrong. And One of the Smartest Guys in the World was wrong.

It wasn’t about saving us. And it wasn’t about enslaving us or herding us into reservations.

It was about killing us.

All of us.

6

I DEBATED WHETHER to travel by day or night for a long time. Darkness is best if you’re worried about them. But daylight is preferable if you want to spot a drone before it spots you.

The drones showed up at the tag end of the 3rd Wave. Cigar-shaped, dull gray in color, gliding swiftly and silently thousands of feet up. Sometimes they streak across the sky without stopping. Sometimes they circle overhead like buzzards. They can turn on a dime and come to a sudden stop, from Mach 2 to zero in less than a second. That’s how we knew the drones weren’t ours.

We knew they were unmanned (or un-Othered) because one of them crashed a couple miles from our refugee camp. A thu-whump! when it broke the sound barrier, an ear-piercing shriek as it rocketed to earth, the ground shuddering under our feet when it plowed into a fallow cornfield. A recon team hiked to the crash site to check it out. Okay, it wasn’t really a team, just Dad and Hutchfield, the guy in charge of the camp. They came back to report the thing was empty. Were they sure? Maybe the pilot bailed before impact. Dad said it was packed with instruments; there wasn’t any room for a pilot. “Unless they’re two inches tall.” That got a big laugh. Somehow it made the horror less horrible, thinking of the Others as being two-inch Borrower types.

I opted to travel by day. I could keep one eye on the sky and another on the ground. What I ended up doing is rocking my head up and down, up and down, side to side, then up again, like some groupie at a rock concert, until I was dizzy and a little sick to my stomach.

Plus there are other things at night to worry about besides drones. Wild dogs, coyotes, bears, and wolves coming down from Canada, maybe even an escaped lion or tiger from a zoo. I know, I know, there’s a Wizard of Oz joke buried in there. Shoot me.

And though it wouldn’t be much better, I do think I’d have a better chance against one of them in the daylight. Or even against one of my own, if I’m not the last one. What if I stumble onto another survivor who decides the best course of action is to go all Crucifix Soldier on anyone they come across?

That brings up the problem of my best course of action. Do I shoot on sight? Do I wait for them to make the first move and risk it being a deadly one? I wonder, not for the first time, why the hell we didn’t come up with some kind of code or secret handshake or something before they showed up—something that would identify us as the good guys. We had no way of knowing they would show up, but we were pretty sure something would sooner or later.

It’s hard to plan for what comes next when what comes next is not something you planned for.

Try to spot them first, I decided. Take cover. No showdowns. No more Crucifix Soldiers!

The day is bright and windless but cold. The sky cloudless. Walking along, bobbing my head up and down, swinging it from side to side, backpack popping against one shoulder blade, the rifle against the other, walking on the outside edge of the median that separates the southbound from the northbound lanes, stopping every few strides to whip around and scan the terrain behind me. An hour. Two. And I’ve traveled no more than a mile.

The creepiest thing, creepier than the abandoned cars and the snarl of crumpled metal and the broken glass sparkling in the October sunlight, creepier than all the trash and discarded crap littering the median, most of it hidden by the knee-high grass so the strip of land looks lumpy, covered in boils, the creepiest thing is the silence.

The Hum is gone.

You remember the Hum.

Unless you grew up on top of a mountain or lived in a cave your whole life, the Hum was always around you. That’s what life was. It was the sea we swam in. The constant sound of all the things we built to make life easy and a little less boring. The mechanical song. The electronic symphony. The Hum of all our things and all of us. Gone.

This is the sound of the Earth before we conquered it.

Sometimes in my tent, late at night, I think I can hear the stars scraping against the sky. That’s how quiet it is. After a while it’s almost more than I can stand. I want to scream at the top of my lungs. I want to sing, shout, stamp my feet, clap my hands, anything to declare my presence. My conversation with the soldier had been the first words I’d said aloud in weeks.

The Hum died on the tenth day after the Arrival. I was sitting in third period texting Lizbeth the last text I will ever send. I don’t remember exactly what it said.

Eleven A.M. A warm, sunny day in early spring. A day for doodling and dreaming and wishing you were anywhere but Ms. Paulson’s calculus class.

The 1st Wave rolled in without much fanfare. It wasn’t dramatic. There was no shock and awe.

The lights just winked out.

Ms. Paulson’s overhead died.

The screen on my phone went black.

Somebody in the back of the room squealed. Classic. It doesn’t matter what time of day it happens—the power goes out, and somebody yelps like the building’s collapsing.

Ms. Paulson told us to stay in our seats. That’s the other thing people do when the power goes out. They jump up to…To what? It’s weird. We’re so used to electricity, when it’s gone, we don’t know what to do. So we jump up or squeal or start jabbering like idiots. We panic. It’s like someone cut off our oxygen. The Arrival had made it worse, though. Ten days on pins and needles waiting for something to happen while nothing is happening makes you jumpy.

So when they pulled the plug on us, we freaked a little more than normal.

Everybody started talking at once. When I announced that my phone had died, out came everyone’s dead phone. Neal Croskey, who was sitting in the back of the room listening to his iPod while Ms. Paulson lectured, pulled the buds from his ears and wondered aloud why the music had died.

The next thing you do when the plug’s pulled, after panicking, is run to the nearest window. You don’t know why exactly. It’s that better-see-what’s-going-on feeling. The world works from the outside in. So if the lights go off, you look outside.

And Ms. Paulson, randomly moving around the mob milling in front of the windows: “Quiet! Back to your seats. I’m sure there’ll be an announcement…”

There was one, about a minute later. Not over the intercom, though, and not from Mr. Faulks, the vice principal. It came from the sky, from them. In the form of a 727 tumbling end over end to the Earth from ten thousand feet until it disappeared behind a line of trees and exploded, sending up a fireball that reminded me of the mushroom cloud of an atomic blast.