These empty stretches are the worst. Cars provide cover. And shelter. I sleep in the undamaged ones (I haven't found a locked one yet). If you can call it sleep. Stale, stuffy air; you can't crack the windows, and leaving the door open is out of the question. The gnaw of hunger. And the night thoughts. Alone, alone, alone.

And the baddest of the bad night thoughts: I'm no alien drone designer, but if I were going to make one, I'd make sure that its detection device was sensitive enough to pick up a body's heat signature through a car roof. It never failed: The moment I started to drift off, I imagined all four doors flying open and dozens of hands reaching for me, hands attached to arms attached to whatever they are. And then I'm up, fumbling with my M16, peeking over the backseat, then doing a 360, feeling trapped and more than a little blind behind the fogged-up windows.

Dawn comes. I wait for the morning fog to burn off, then sip some water, brush my teeth, double-check my weapons, inventory my supplies, and hit the road again. Look up, look down, look all around. Don't pause at the exits. Water's fine for now. No way am I going anywhere near a town unless I have to.

For a lot of reasons.

You know how you can tell when you're getting close to one? The smell. You can smell a town from miles away.

It smells like smoke. And raw sewage. And death.

In the city it's hard to take two steps without stumbling over a corpse. Funny thing: People die in clumps, too.

I begin to smell Cincinnati about a mile before spotting the exit sign. A thick column of smoke rises lazily toward the cloudless sky.

Cincinnati is burning.

I'm not surprised. After the 3rd Wave, the second most common thing you found in cities, after the bodies, were fires. A single lightning strike could take out ten city blocks. There was no one left to put the fires out.

My eyes start to water. The stench of Cincinnati makes me gag. I stop long enough to tie a rag around my mouth and nose and then quicken my pace. I pull the rifle off my shoulder and cradle it as I quickstep. I have a bad feeling about Cincinnati. The old voice inside my head is awake.

Hurry, Cassie. Hurry.

And then, somewhere between Exits 17 and 18, I find the bodies.

9.

THERE ARE THREE OF THEM, not in a clump like city folk, but spaced out in the median strip. The first one is an older guy, around my dad's age, I guess. Wearing blue jeans and a Bengals warm-up. Facedown, arms outstretched. He was shot in the back of the head.

The second, about a dozen feet away, is a young woman, a little older than I am and dressed in a pair of men's pajama pants and Victoria's Secret tee. A streak of purple in her short-cropped hair. A skull ring on her left index finger. Black nail polish, badly chipped. And a bullet hole in the back of her head.

Another few feet and there's the third. A kid around eleven or twelve. Brand-new white basketball high-tops. Black sweatshirt. Hard to tell what his face used to look like.

I leave the kid and go back to the woman. Kneel in the tall brown grass beside her. Touch her pale neck. Still warm.

Oh no. No, no, no.

I trot back to the first guy. Kneel. Touch the palm of his outstretched hand. Look over at the bloody hole between his ears. Shiny. Still wet.

I freeze. Behind me, the road. In front of me, more road. To my right, trees. To my left, more trees. Clumps of cars on the southbound lane, the nearest grouping about a hundred feet away. Something tells me to look up. Straight up.

A fleck of dull gray against the backdrop of dazzling autumnal blue.

Motionless.

Hello, Cassie. My name is Mr. Drone. Nice to meet you!

I stand up, and when I stand up-the moment I stand up; if I had stayed frozen there a millisecond longer, Mr. Bengals and I would be sporting matching holes-something slams into my leg, a hot punch just above my knee that knocks me off balance, sending me sprawling backward onto my butt.

I didn't hear the shot. There was the cool wind in the grass and my own hot breath under the rag and the blood rushing in my ears-that's all there was before the bullet struck.

Silencer.

That makes sense. Of course they'd use silencers. And now I have the perfect name for them: Silencers. A name that fits the job description.

Something takes over when you're facing death. The front part of your brain lets go, gives up control to the oldest part of you, the part that takes care of your heartbeat and breathing and the blinking of your eyes. The part nature built first to keep your ass alive. The part that stretches time like a gigantic piece of toffee, making a second seem like an hour and a minute longer than a summer afternoon.

I lunge forward for my rifle-I had dropped the M16 when the round punched home-and the ground in front of me explodes, showering me with shredded grass and hunks of dirt and gravel.

Okay, forget the M16.

I yank the Luger from my waistband and do a sort of running hop-or a hopping run-toward the closest car. There isn't much pain-although my guess is that we're going to get very intimate later-but I can feel the blood soaking into my jeans by the time I reach the car, an older model Buick sedan.

The rear windshield shatters as I dive down. I scoot on my back till I'm all the way under the car. I'm not a big girl by any stretch, but it's a tight fit, no room to roll over, no way to turn if he shows up on the left side.

Cornered.

Smart, Cassie, real smart. Straight As last semester? Honor roll? Riiiiiight.

You should have stayed in your little stretch of woods in your little tent with your little books and your cute little mementos. At least when they came for you, there'd be room to run.

The minutes spin out. I lie on my back and bleed onto the cold concrete. Rolling my head to the right, to the left, raising it a half inch to look past my feet toward the back of the car. Where the hell is he? What's taking so long? Then it hits me: He's using a high-powered sniper rifle. Has to be. Which means he could have been over a half mile away when he shot me.

Which also means I have more time than I first thought. Time to come up with something besides a blubbery, desperate, disjointed prayer.

Make him go away. Make him be quick. Let me live. Let him end it...

Shaking uncontrollably. I'm sweating; I'm freezing cold.

You're going into shock. Think, Cassie.

Think.

It's what we're made for. It's what got us here. It's the reason I have this car to hide under. We are human.

And humans think. They plan. They dream, and then they make the dream real.

Make it real, Cassie.

Unless he drops down, he won't be able to get to me. And when he drops down...when he dips his head to look at me...when he reaches in to grab my ankle and drag me out...

No. He's too smart for that. He's going to assume I'm armed. He wouldn't risk it. Not that Silencers care whether they live or die...or do they care? Do Silencers know fear? They don't love life-I've seen enough to prove that. But do they love their own lives more than they love taking someone else's?

Time stretches out. A minute's longer than a season. What's taking him so damn long?

It's an either/or world now. Either he's coming to finish it or he isn't. But he has to finish it, doesn't he? Isn't that the reason he's here? Isn't that the whole friggin' point?

Either/or: Either I run-or hop or crawl or roll-or I stay under this car and bleed to death. If I risk escape, it's a turkey shoot. I won't make it two feet. If I stay, same result, only more painful, more fearful, and much, much slower.

Black stars blossom and dance in front of my eyes. I can't get enough air into my lungs.

I reach up with my left hand and yank the cloth from my face.

The cloth.

Cassie, you're an idiot.

I set the gun down beside me. That's the hardest part-making myself let go of the gun.

I lift my leg, slide the rag beneath it. I can't lift my head to see what I'm doing. I stare past the black, blossoming stars at the grimy guts of the Buick as I pull the two ends together, cinch them tight, as tight as I can, and fumble with the knot. I reach down and explore the wound with my fingertips. It's still bleeding, but a trickle compared to the bubbling gusher I had before tying off the tourniquet.

I pick up the gun. Better. My eyesight clears a little, and I don't feel quite so cold. I shift a couple of inches to the left; I don't like lying in my own blood.

Where is he? He's had plenty of time to finish this...

Unless he is finished.

That brings me up short. For a few seconds, I totally forget to breathe.

He's not coming. He's not coming because he doesn't need to come. He knows you won't dare come out, and if you don't come out and run, you won't make it. He knows you'll starve or bleed to death or die of dehydration.

He knows what you know: Run = die. Stay = die.

Time for him to move on to the next one.

If there is a next one.

If I'm not the last one.

Come on, Cassie! From seven billion to just one in five months? You're not the last, and even if you are the last human being on Earth-especially if you are-you can't let it end this way. Trapped under a goddamned Buick, bleeding until all the blood is gone-is this how humanity waves good-bye?

Hell no.

10.

THE 1ST WAVE took out half a million people.

The 2nd Wave put that number to shame.

In case you don't know, we live on a restless planet. The continents sit on slabs of rock, called tectonic plates, and those plates float on a sea of molten lava. They're constantly scraping and rubbing and pushing against one another, creating enormous pressure. Over time the pressure builds and builds, until the plates slip, releasing huge amounts of energy in the form of earthquakes. If one of those quakes happens along one of the fault lines that ring every continent, the shock wave produces a superwave called a tsunami.

Over 40 percent of the world's population lives within sixty miles of a coastline. That's three billion people.

All the Others had to do was make it rain.

Take a metal rod twice as tall as the Empire State Building and three times as heavy. Position it over one of these fault lines. Drop it from the upper atmosphere. You don't need any propulsion or guidance system; just let it fall. Thanks to gravity, by the time it reaches the surface, it's traveling twelve miles per second, twenty times faster than a speeding bullet.

It hits the surface with a force one billion times greater than the bomb dropped on Hiroshima.

Bye-bye, New York. Bye, Sydney. Good-bye, California, Washington, Oregon, Alaska, British Columbia. So long, Eastern Seaboard.

Japan, Hong Kong, London, Rome, Rio.

Nice to know you. Hope you enjoyed your stay!

The 1st Wave was over in seconds.

The 2nd Wave lasted a little longer. About a day.

The 3rd Wave? That took a little longer-twelve weeks. Twelve weeks to kill...well, Dad figured 97 percent of those of us unlucky enough to have survived the first two waves.

Ninety-seven percent of four billion? You do the math.

That's when the Alien Empire descended in their flying saucers and started blasting away, right? When the peoples of the Earth united under one banner to play David versus Goliath. Our tanks against your ray guns. Bring it on!

We weren't that lucky.

And they weren't that stupid.

How do you waste nearly four billion people in three months?

Birds.

How many birds are there in the world? Wanna guess? A million? A billion? How about over three hundred billion? That's about seventy-five birds for each man, woman, and child still alive after the first two waves.

There are thousands of species of bird on every continent. And birds don't recognize borders. They also crap a lot. They crap five or six times a day. That's over a trillion little missiles raining down each day, every day.

You couldn't invent a more efficient delivery system for a virus that has a 97 percent kill rate.

My father thought they must have taken something like Ebola Zaire and genetically altered it. Ebola can't spread through the air. But change a single protein and you can make it airborne, like the flu. The virus takes up residence in your lungs. You get a bad cough. Fever. Your head starts to hurt. Hurt bad. You start spitting up little drops of virus-laden blood. The bug moves into your liver, your kidneys, your brain. You're packing a billion of them now. You've become a viral bomb. And when you explode, you blast everyone around you with the virus. They call it bleeding out. Like rats fleeing a sinking ship, the virus erupts out of every opening. Your mouth, your nose, your ears, your ass, even your eyes. You literally cry tears of blood.

We had different names for it. The Red Death or the Blood Plague. The Pestilence. The Red Tsunami. The Fourth Horseman. Whatever you wanted to call it, after three months, ninety-seven out of every hundred people were dead.