The same disaster of spoilage, the same stench of rats and rotted food, the same fitful swirl of dust in the murky light pushing through the smudged windows, every out-of-place thing in its place, undisturbed.

Still.

Something was different.

I was standing in the little pool of broken glass just inside the doorway. I didn’t see it. I didn’t hear it. I didn’t smell or feel it. But I knew it.

Something was different.

It’s been a long time since humans were prey animals. A hundred thousand years or so. But buried deep in our genes the memory remains: the awareness of the gazelle, the instinct of the antelope. The wind whispers through the grass. A shadow flits between the trees. And up speaks the little voice that goes, Shhhh, it’s close now. Close.

I don’t remember swinging the M16 from my shoulder. One minute it was hanging behind my back, the next it was in my hands, muzzle down, safety off.

Close.

I’d never fired it at anything bigger than a rabbit, and that was a kind of experiment, to see if I could actually use the thing without blowing off one of my own body parts. Once I shot over the heads of a pack of feral dogs that had gotten a little too interested in my campsite. Another time nearly straight up, sighting the tiny, glowering speck of greenish light that was their mothership sliding silently across the backdrop of the Milky Way. Okay, I admit that was stupid. I might as well have erected a billboard with a big arrow pointing at my head and the words YOO-HOO, HERE I AM!

After the rabbit experiment—it blew that poor damn bunny apart, turning Peter into this unrecognizable mass of shredded guts and bone—I gave up the idea of using the rifle to hunt. I didn’t even do target practice. In the silence that had slammed down after the 4th Wave struck, the report of the rounds sounded louder than an atomic blast.

Still, I considered the M16 my bestest of besties. Always by my side, even at night, burrowed into my sleeping bag with me, faithful and true. In the 4th Wave, you can’t trust that people are still people. But you can trust that your gun is still your gun.

Shhh, Cassie. It’s close.

Close.

I should have bailed. That little voice had my back. That little voice is older than I am. It’s older than the oldest person who ever lived.

I should have listened to that voice.

Instead, I listened to the silence of the abandoned store, listened hard. Something was close. I took a tiny step away from the door, and the broken glass crunched ever so softly under my foot.

And then the Something made a noise, somewhere between a cough and a moan. It came from the back room, behind the coolers, where my water was.

That’s the moment when I didn’t need a little old voice to tell me what to do. It was obvious, a no-brainer. Run.

But I didn’t run.

The first rule of surviving the 4th Wave is don’t trust anyone. It doesn’t matter what they look like. The Others are very smart about that—okay, they’re smart about everything. It doesn’t matter if they look the right way and say the right things and act exactly like you expect them to act. Didn’t my father’s death prove that? Even if the stranger is a little old lady sweeter than your great-aunt Tilly, hugging a helpless kitten, you can’t know for certain—you can never know—that she isn’t one of them, and that there isn’t a loaded .45 behind that kitten.

It isn’t unthinkable. And the more you think about it, the more thinkable it becomes. Little old lady has to go.

That’s the hard part, the part that, if I thought about it too much, would make me crawl into my sleeping bag, zip myself up, and die of slow starvation. If you can’t trust anyone, then you can trust no one. Better to take the chance that Aunty Tilly is one of them than play the odds that you’ve stumbled across a fellow survivor.

That’s friggin’ diabolical.

It tears us apart. It makes us that much easier to hunt down and eradicate. The 4th Wave forces us into solitude, where there’s no strength in numbers, where we slowly go crazy from the isolation and fear and terrible anticipation of the inevitable.

So I didn’t run. I couldn’t. Whether it was one of them or an Aunt Tilly, I had to defend my turf. The only way to stay alive is to stay alone. That’s rule number two.

I followed the sobbing coughs or coughing sobs or whatever you want to call them till I reached the door that opened to the back room. Hardly breathing, on the balls of my feet.

The door was ajar, the space just wide enough for me to slip through sideways. A metal rack on the wall directly in front of me and, to the right, the long narrow hallway that ran the length of the coolers. There were no windows back here. The only light was the sickly orange of the dying day behind me, still bright enough to hurl my shadow onto the sticky floor. I crouched down; my shadow crouched with me.

I couldn’t see around the edge of the cooler into the hall. But I could hear whoever—or whatever—it was at the far end, coughing, moaning, and that gurgling sob.

Either hurt badly or acting hurt badly, I thought. Either needs help or it’s a trap.

This is what life on Earth has become since the Arrival. It’s an either/or world.

Either it’s one of them and it knows you’re here or it’s not one of them and he needs your help.

Either way, I had to get up and turn that corner.

So I got up.

And I turned the corner.

4

HE LAY SPRAWLED against the back wall twenty feet away, long legs spread out in front of him, clutching his stomach with one hand. He was wearing fatigues and black boots and he was covered in grime and shimmering with blood. There was blood everywhere. On the wall behind him. Pooling on the cold concrete beneath him. Coating his uniform. Matted in his hair. The blood glittered darkly, black as tar in the semidarkness.

In his other hand was a gun, and that gun was pointed at my head.

I mirrored him. His handgun to my rifle. Fingers flexing on the triggers: his, mine.

It didn’t prove anything, his pointing a gun at me. Maybe he really was a wounded soldier and thought I was one of them.

Or maybe not.

“Drop your weapon,” he sputtered at me.

Like hell.

“Drop your weapon!” he shouted, or tried to shout. The words came out all cracked and crumbly, beaten up by the blood rising from his gut. Blood dribbled over his bottom lip and hung quivering from his stubbly chin. His teeth shone with blood.

I shook my head. My back was to the light, and I prayed he couldn’t see how badly I was shaking or the fear in my eyes. This wasn’t some damn rabbit that was stupid enough to hop into my camp one sunny morning. This was a person. Or, if it wasn’t, it looked just like one.

The thing about killing is you don’t know if you can actually do it until you actually do it.

He said it a third time, not as loud as the second. It came out like a plea.

“Drop your weapon.”

The hand holding his gun twitched. The muzzle dipped toward the floor. Not much, but my eyes had adjusted to the light by this point, and I saw a speck of blood run down the barrel.

And then he dropped the gun.

It fell between his legs with a sharp cling. He brought up his empty hand and held it, palm outward, over his shoulder.

“Okay,” he said with a bloody half smile. “Your turn.”

I shook my head. “Other hand,” I said. I hoped my voice sounded stronger than I felt. My knees had begun to shake and my arms ached and my head was spinning. I was also fighting the urge to hurl. You don’t know if you can do it until you do it.