Then he drove me home and walked me to the front door. And at the porch, he stopped.

"Can I kiss you?" he asked hoa.r.s.ely. There was so much in his expression, and I could read it all. He liked me. He really liked me. He didn't want to mess this up. He thought it might be too soon, but he wanted to kiss me. He wanted to know that I felt what he felt. It was a real part of the experiment, this kiss. It was: Does me + Steven + dating = chemistry?

That's what kissing is supposedly for, on a biological level. It's a taste test, to see if you'd be a good match.

"Yes," I said, and stepped closer to him. "You can kiss me."

Slowly he lowered his head until his lips almost touched mine. He smiled, and I felt light-headed with how much I found I wanted this. I dragged my bottom lip between my teeth to wet it and smiled too. Breathless. Waiting.

"Okay," he whispered, his breath hot against my cheek. "Here we go."

His mouth came down on mine gently, without pressure, and I don't have words to describe what it was like outside of warm and wonderful and alive, and none of those words even come close. After a minute our mouths opened and my tongue touched his, and the furthest thing from my mind would have been the words ew or no or gross. He tasted like red curry and sweet tea. Electricity zinged down my body and pooled low in my belly and I thought, Wow. So this is how it feels. All this time, I'd wondered. I was almost 18 years old and I'd never felt so connected with another person.

I curled my hand around the solidness of his shoulder and pulled him closer. He made a small rough noise deep in his chest and changed the angle, and our gla.s.ses banged against each other. We broke away from each other, laughing.

"That was . . . ," he started.

"Spectacular," I breathed.

"Spectacular," he repeated, his brown eyes sparkling. Because the results of our experiment were conclusive: Me + Steven + dating = spontaneous combustion He tucked a strand of my hair behind my ear, his thumb lingering on my cheek. I shivered. I wanted to kiss him again.

"Good night, Lex," he said, and then he turned abruptly and jogged back to his car. He sat there for a few minutes without driving off, and I wondered what he was doing until my phone buzzed with a series of rapid-fire texts. Which read: There are some things I didn't get to say before.

You are an amazing girl, Lex. You're smart and funny and kind and beautiful. You're the whole package.

Thanks for saying yes.

I'll see you tomorrow?

I texted back that yes, I would love to see him tomorrow. We grinned at each other through the gla.s.s of his car window, and he drove away, and I went inside.

It was June 20.

I'd get six months with Steven, six months to the day, 183 days of kisses, before the equation would change again.

TY AND I ARE WALKING IN THE WOODS. There aren't a lot of woods to choose from in Nebraska-we're more of a plains-type state-but when we were kids Mom and Dad took us to this one part of the Nebraska National Forest where there were tall trees and a lake and a campground. We camped in tents, Ty and me in one and our parents in another. I can't remember how old we were, but little, I think. Little enough that our very own tent with just the two of us seemed like the greatest adventure. We stayed up half the night whispering, making shadow puppets with our flashlights, gazing up through the see-through mesh at the top of our tent at the dark shapes of the tree branches swaying over us, imagining the stars. The next morning, we got up early to fish on the lake. Ty caught five fish to my four, but he threw his back into the water. He was tenderhearted, even then, too sweet to murder an innocent fish. But Dad bashed mine in the head with a special hammer and fried them up over the campfire for lunch. And then he said to Ty, "This is reality. Eat up."

Dad's not so much with the sentimentality. My apple didn't fall far from his tree, I guess.

Anyway. It's those woods, I think. Where Ty and I are walking now.

He's wearing a white tee and dark jeans.

The sun is going down somewhere behind us. I don't know where we're walking. I'm wearing my backpack, and it's heavy. I want to stop, just so I can get a good look, in the fading light, at Ty's face. I'm starting to forget it. The shape of his nose. His ears. His lips, which were perpetually chapped. I used to say to him, "Dude, invest in some ChapStick already." Now I just want to memorize him, every detail I can get, chapped lips and all, to push the image of him yellow and stiff and covered in a layer of funeral-home makeup out of my brain.

"Hey," I say to him. "Can we rest for a minute?"

He turns to me. "You're tired already? We only just started." But he sits down on a large rock. "Give me some of your water."

I find I'm carrying a large water bottle. I hold on to it. "What's the magic word?" I tease.

"Puh-leeze," he says, reaching, smiling, and I shake my head.

"Nope."

"Moist," he says. "The magic word is moist."

"Ew. No."

"It's not delusion, I'll tell you that much."

"Shut up. I was improvising."

"What word are you going to write your essay about?"

"I'm not planning to do that a.s.signment," I inform him.

"You. Aren't going to do your homework. You."

"How do you even know about that?"

He shrugs. "What word?" he persists. "What word would you write about?"

"Doofus," I retort.

"Brilliant. It fits you," he says with a roll of his eyes. "Now give me the water, Lex. I'm dying here."

I arch an eyebrow at him.

He smirks. "Figuratively speaking."

I hand him the water. He gulps down like half of it, wipes his mouth with the back of his hand in a gesture so familiar it makes my chest ache, and hands the bottle back.

I miss you, I want to say. It's on the tip of my tongue, but I think, If I call attention to the fact that this is a dream, then I'll wake up.

I don't want to wake up.

Something snaps in the woods. A flock of birds startles from a tree and takes flight, their wings crackling in the air. The light is fading by the minute. I look at Ty. He's staring off into the darkest part of the woods.

"We should go," he says as he gets to his feet.

"Okay."

We start walking again. I still don't know where we're going. There doesn't seem to be a path, but Ty acts like he knows the way. He keeps looking over his shoulder, behind us, like he's afraid, and this makes me afraid. It's suddenly so dark. The shadows are coming at us from every direction.

We walk faster. I'm out of breath. I stumble on a tree root or something.

I fall.

Ty grabs my hand and helps me to my feet. In the woods behind us there are more snapping branches and crunching leaves, the sounds of something moving toward us. Something stalking us. Something big.

I've hurt my ankle. Bad.

"It's a bear," Ty says, when I open my mouth to tell him that I'm not going to be able to run. "A grizzly."

"There aren't grizzlies in Nebraska."

"We should climb that tree." Ty picks a huge, spreading oak, which also shouldn't be in these woods. "Can you climb it?"

I don't have any experience climbing trees, but I try. I scramble up the trunk, ignoring the pain in my ankle, reaching at branches. Ty follows behind me, helping me balance, pushing me up, coaching me. But I'm slow. I don't climb high enough or fast enough. I'm clumsy.

"Hurry!" Ty cries. "It's here." It's so dark I can hardly see, but I can make out the huge silver-tipped shoulders of the bear below us, impossibly big. It makes a kind of chuffing noise, like a bark. It stretches up toward us. Then it has Ty's foot in its mouth. It starts to pull him out of the tree.

I grab his arms. I hold on.

Ty looks into my eyes. He smiles, and it's a sad smile, because he knows how this is going to end. We both do.

He says, "Don't watch. Stay up here, where it's safe. It will be over soon."

"Ty, no." I clutch his arms tighter. "Don't."

The bear is too strong. I can't hold him. He's yanked away. He falls. In the blackness of the forest, I hear him scream.

This is a dream, I tell myself. This is only a dream. He can't die again.

But he does. I hear the bear kill him. There are roars, Ty's yells of pain and terror, the ripping of fabric and the cracking of bones. I press my face into the rough bark of the oak tree, and I squeeze my eyes closed, and I listen to him die. Even then, in my dreams, I can't cry for him. I can't stop it. I can't help.

I am completely useless, I think. I can't save him.

Then, when it's over, when the woods fall silent again, I wake up. In my own room. In the dark. Alone again.

I've been having these dreams for weeks now. They're always the same, me and Ty, doing something we used to do, talking the way we used to talk, and then, after a while, something goes wrong and Ty dies. So far he's died in a plane crash and gotten shot by a gang member and been struck by lightning during a thunderstorm. In one he fell down a set of stairs and broke his neck. In another he got hit by a car while we were riding our bikes to school. It's like my own personal version of Kenny from South Park, except that Ty never dies the way he actually died. And every time he dies, every time I watch him, it feels real.

My stomach churns like I might vomit. I take a few deep, steadying breaths, like when Dad was in his Pilates phase and made us all learn to breathe from our core, and I sit up. I push my tangled hair out of my face. And then my heart lodges itself in my throat like a chunk of ice.

In the dim light from my bedroom window, I see a figure standing there. A silhouette. A person.

"Ty?" I croak.

The figure shifts slightly, as if he's been looking out at the street but now he's turning around. He doesn't speak. I fumble for my gla.s.ses on the nightstand. I'm bat blind without my gla.s.ses. When I was a kid I used to freak myself out in the middle of the night, thinking that if a monster came out of my closet to get me, I wouldn't see it until it was too late.

My fingers close around the frames. I unfold them carefully, bring them to my face, and look again at the window.

He's not there. There's just the shadow from the weeping willow tree outside.

I fall back on my pillow.

A shadow. A stupid shadow. From the stupid tree.

Ty's not ever going to be here when I open my eyes, I tell myself sternly. Not for real. No matter what I dream about.

I turn onto my side, my face to the wall. I will myself to go back to sleep. I go with the tried and true method: numbers. 0, 1, 1, 2, 3, 5, 8, 13, 21, each number the sum of the two numbers before it. The Fibonacci sequence, it's called, after an Italian mathematician who wrote about it in 1202. Fibonacci numbers are everywhere, in nature, even, in the pattern of leaves on a stem or the way the circles present themselves on the skin of a pineapple or the arrangement of seeds in a pinecone. Math. Safe, reliable math.

There is nothing more real than numbers.

My heartbeat starts to slow. My shoulders relax. I let myself breathe.

34. 55. 89. 144.

I remember that I'm wearing my gla.s.ses, and I take them off, fold them, and reach behind me to set them on the nightstand. The room goes dark and blurry, like an impressionist painting, colors but no distinct lines. Like a Van Gogh painting, I used to tell myself. Starry Freaking Night. I pull the covers up to my chin.

233. 377. 610. 987. 1,597. 2,584.

And it's right then, as my eyelids begin to get heavy, as I start to drift off to the gray s.p.a.ce where Ty isn't dead, that I smell it.

A mix of sandalwood and basil and a hint of lemon.

Brut.

I smell my brother's cologne.

SOMEONE'S KNOCKING ON THE FRONT DOOR.

I ignore it. I've got my hands full, literally. My sleeves are rolled up, and I'm wearing the rubber gloves and ap.r.o.n and everything, up to my elbows in hot, soapy water, in the middle of the mountain of dishes that's been piling up on our kitchen counter all week, since neither Mom nor I have the energy for dishes.

I haven't been sleeping well.

Now, I've decided, is not a good time for a visit from the sympathy parade.

Whoever-it-is pounds on the door again.

I'm annoyed. Mom's still asleep. Yes, it's after three o'clock in the afternoon on a Sunday, but she's been out cold all day. She didn't even get up for church, which is a bad sign. Until now she's always managed to get up for G.o.d.

The knock comes again.

Hey, that's okay, I think, still ignoring it, putting a dish in the dishwasher. Mom doesn't have to go to church. We're allowed to be antisocial. We're permitted to sleep as much as we want to. We get a pa.s.s. It's the only real perk that comes with the whole lose-your-brother gig: an indeterminate amount of time to make excuses. I don't have to open the door.

But this knock. It's loud. Persistent. A knock that isn't going away anytime soon.

Then it occurs to me that whoever-it-is could be bringing us dinner. That's how American culture teaches people to deal with a death: They bring a ca.s.serole. A pie. A fruit salad. This ritual provides the person giving it the feeling that they've done something useful for us. They've fed us. That's how they show us they care.

The first week people cared a lot. We had so much food that most of it went bad before we could eat it. Mom and I weren't even remotely hungry at that point; we just kind of sat in various positions on various pieces of furniture, and people would orbit around us, bringing us tissues, water, every few hours asking us if we thought we might eat something. I always waved the food away, but Mom tried. She wanted to be polite. I'd watch her sit at the table, forcing herself to go through the motions of eating, chewing each bite carefully, swallowing, trying to smile and reaffirm how good she thought it was, how very thoughtful.

The second week the people were mostly gone, and we picked at the best stuff they'd left us: the chocolate cream pies, the roast chickens, the sweet rolls. I tossed the rest. By the third or fourth week I started to get a bit of my appet.i.te back, but right about then was when the food stopped coming.

People move on with their lives.

Even if we can't.