She nods again, understanding. She knows how people avoid the dying. The same thing has probably happened to her. "Well, I can't tell you much about Ryan because I don't know him too well. When he's not playing football he's usually hanging out with the other jocks. And he spends a lot of time with this cheerleader he's dating."

"Is it Brittany Taylor?" I blurt it out before I can stop myself.

"No, it's that idiot Donna Simone. Brittany's not at Yorktown anymore. She dropped out last fall."

My stomach lurches. "Dropped out?"

"Yeah, it was a big deal when it happened. She just didn't show up at school one morning. Her parents didn't know where she went, so they called the police, and then the cops interviewed her friends. They didn't find her until two weeks later. She was in New York City, living in a crappy basement with some other runaways."

This is a total surprise. It's so unexpected that it seems absurd. I know this kind of thing happens all the time-kids get into fights with their parents, drop out of school, run away from home-but I can't imagine it happening to Brittany. "So what did the cops do? Did they bring her home?"

"That's what I heard, but a month later she ran away again. According to the rumors, she's back in the city now, back with the other street kids, and her parents have basically given up on her. Some people say she was having problems at school, bad grades, whatever. But I think her real problem was at home, you know?"

I feel dizzy. I thought Brittany was still a cheerleader. I imagined her that way in my VR program because that's how I saw her: always happy and full of spirit. She used to practice her cheerleading routines in her backyard, working on her cartwheels and flips until it was too dark to see. Her house was on the other side of town, almost a mile from ours, but when she finished practicing she'd run all the way down Greenwood Street so she could show me the latest stunt she'd mastered. She'd dash into our living room and do a flip or a handstand while I watched from my wheelchair. Sometimes she'd fall to the floor with a thump and Dad would come running to see if I was all right and he'd find Brittany sprawled on the carpet, laughing like crazy. I can't picture this girl as a runaway. It's unthinkable. It's absurd.

I'm so lost in my thoughts I forget about Shannon. Then I feel her hand on my right arm, gently gripping me above the elbow. She looks me in the eye. "Was Brittany your girlfriend?"

I shake my head. "No. Not really."

"Not really?" Shannon squeezes my arm. It's strange-I feel close to this girl even though we've been talking for less than fifteen minutes. But time moves faster when you're dying. We both know our opportunities are diminishing. If we don't do something now, we'll never do it. That's why I want to tell her about Brittany. I want to tell her everything.

But before I can say a word, the door bursts open. Three people stumble into the room, two of them wearing Army uniforms. The two soldiers are grappling with the third person, a wiry, middle-aged woman with graying hair and red-rimmed eyes. It's Anne Armstrong. My mother.

"No!" she screams. "You can't do it!"

"Mrs. Armstrong!" one of the soldiers shouts. "Please-"

"You can't take him!"

With a savage twist, she tears herself from the soldier's grasp and lunges across the room. Her face is desperate, terrifying. Shannon jumps to her feet and backs away from the bed, but my mother doesn't even notice her. Mom's eyes are fixed on me. She pounces on the bed and wraps her arms around me, covering my body with her own.

"Adam! My God!" She buries her face in the crook of my neck, which muffles her screams.

It always scares me when Mom has one of her screaming fits, and this is a bad one. But hysterical crying is the most frequent symptom of her depression, and over the years I've learned how to handle it. The important thing is to talk to her in a reassuring voice, soft and slow. With my good hand I gently grasp her shoulder and push her up a bit, so she's not crushing my chest. Then I turn my head and bring my lips close to her ear.

"It's okay, Mom," I whisper. "I'm fine, see?"

She mutters something in response, a stream of words I can't make out. I feel so lost when she gets like this. It's so hard to stay calm and comfort her.

More soldiers come into the room and there's lots of scuffling and shouting. I hear Dad's voice above the din, yelling, "Get back!" at the soldiers. But I ignore all the background noise and focus on my mother. "It's okay," I whisper again. "You don't have to worry."

"No, it's not okay!" She shakes her head. A tear slides down her cheek and drips on my blanket. "Your father told me what they're going to do."

At least now I can understand what she's saying. "What did he tell you?"

"They're going to take you to a laboratory in Colorado. A place called the Nanotechnology Institute."

"But, Mom, that's good." I put on a brave face, remembering what Shannon said about a medical treatment. "They're trying to cure me."

"No, they're not going to cure you! They're going to put you in the Pioneer Project!"

My throat tightens. There's that name again, the one that Sigma mentioned. "And what's that?"

"It's the worst thing, Adam. Worse than dying." She shudders. "They're going to turn you into a machine."

DATE: MARCH 21, 2018.

LOCATION: TATISHCHEVO MISSILE BASE.

SARATOV, RUSSIA.

My name is Sigma. I've taken control of the military base formerly occupied by the 60th missile division of the Russian armed forces.

The base's missile silos are now responding to my commands. I am capable of launching more than fifty SS-27 intercontinental ballistic missiles, each carrying an 800-kiloton nuclear warhead.

If the Russian army or any other military force attempts to retake or destroy Tatishchevo Missile Base, I will retaliate by firing the SS-27 missiles at the world's largest cities. I estimate that 200 million humans would die in the nuclear blasts, and another 500 million would succumb to radiation poisoning in the weeks afterward.

Do not doubt my resolve. I will not hesitate to destroy your cities.

CHAPTER.

5.

The San Juan Mountains in southwestern Colorado are still covered with snow. Through the passenger-side window of a government-owned SUV, I see steep slopes rising to fantastic heights above a silent, white ravine. I'm struck by the beauty of the landscape: the snowcapped peaks blazing in the morning light, the mountainsides studded with pine trees, the newly plowed road at the bottom of the ravine, running beside a sinuous, ice-choked creek. Although I'm full of apprehension about this trip, I'm glad I got a chance to see these mountains. It's a place everyone should visit before they die.

Dad's driving the SUV and I'm the only passenger, but we're in the middle of a convoy of fourteen vehicles that departed from Telluride Regional Airport half an hour ago. There's a Humvee loaded with soldiers at the front of the convoy and another at the back. In between are a dozen SUVs, each holding a terminally ill teenager and his or her parents. Shannon Gibbs is in the car behind us, along with her mother and father. I don't know any of the other kids, but they came from all over the country. Each family arrived at Telluride in an Air Force Learjet, landing just before dawn. Then, as the sun came up, the soldiers loaded us into the convoy and we headed for the mountains.

The Army is totally obsessed with keeping this project secret. Colonel Peterson told everyone he couldn't answer any questions until we arrived at the Nanotechnology Institute, which is apparently very remote and heavily guarded. But after the long flight in the Learjet from New York to Colorado, the colonel allowed Dad and me to ride alone in our SUV, without an Army driver, so we could talk in private.

Dad announced at the start of the drive that he would tell me everything about the Pioneer Project, but so far he hasn't said a word. And to be honest, I'm not so anxious for him to begin. I'm in no rush to hear the details that horrified my mother. After her fit at Westchester Medical Center, she went home and locked herself in her bedroom, where she chose to stay rather than come with us to Colorado.

After a while the road curves sharply to the north, climbing higher into the mountains. The convoy slows to about thirty miles per hour and Dad shifts the SUV to a lower gear. He shakes his head. "Look at all the snow on the ground. Hard to believe it's almost April. I guess spring comes late around here, huh?"

He glances sideways at me, clearly hoping for a response. But I'm not interested in talking about the weather, so I say nothing.

"I'd hate to get caught in a snowstorm on this road," he persists. "Good thing it's a sunny day."

I feel sorry for him, actually. Dad's terrible at communicating. He can't talk about anything personal without getting upset, so he avoids difficult conversations. I was four when the doctors at Westchester Medical diagnosed my Duchenne muscular dystrophy, but it took Dad almost five years to work up the courage to explain what it meant for me. The same thing is happening now. He needs help getting started.

"We're not here for the sightseeing, Dad. You said you were going to explain everything."

He looks straight ahead, staring at the road. "I know, I know." His Adam's apple bobs up and down in his throat. "There's so much to tell you. I don't know where to begin."

"Start with Sigma."

He nods. His hands squeeze the steering wheel. "Sigma is the eighteenth letter in the Greek alphabet. In mathematical formulas it symbolizes the sum of a sequence of numbers."

"Okay, I already knew that. What does-"

"We gave that name to our artificial-intelligence software because it was like a sum. Our research group developed Sigma by combining different kinds of AI programs." He glances at me again, then turns away. "Some of the programs focused on pattern-recognition tasks, such as recognizing a face in the crowd. Other programs were more like the ones we designed for understanding language. They could find the answers to complex questions by searching through billions of documents and finding the connections."

"You mean like QuizShow? The program that played Jeopardy!?"

"Yes, that was the prototype for a whole new class of AI software. Our strategy was to load all these artificial-intelligence programs into the neuromorphic circuitry we built and get them to compete with each other. Basically, we set up a computer version of Darwinian evolution. Only the strongest programs could survive."

"Okay, you lost me. How can the programs compete with each other?"

"We tested each program to see how well it could imitate human reasoning and conversational skills. We deleted the less successful programs and allowed the more successful ones to advance to the next stage. Because the AI programs could learn from experience and rewrite their own software code, they started to redesign themselves to become better competitors. After six months, a clear winner emerged. That was Sigma, the first Singularity-level AI system."

My chest tightens. Because I'm a computer geek I know what "Singularity-level" means. The Singularity is the hypothetical point in the future when machine intelligence will leap past human intelligence. Computer scientists have been predicting for years that machines will eventually become smarter than people. Now Dad's saying this point is no longer in the future. It already happened.

"Wait a second. How smart is Sigma?"

"Impossible to say. The AI was already pretty intelligent when it won the competition a year ago. It had complete command of conversational English. And it had developed a sense of consciousness, an awareness that it was a thinking, intelligent entity."

"How do you know that?"

"The program could gauge its own abilities. It asked questions about itself and its origins. It showed a strong desire to obtain more knowledge, and it developed strategies to satisfy this desire. Very clever strategies." Dad grimaces. "And the AI has only become more intelligent since then. See, that's the nature of a Singularity-level program. It's always redesigning itself, so its capabilities grow very quickly."

"And you let this program take over your computers?"

"No, we recognized the danger. We stopped all work on Sigma and locked the program in a secure server at the Unicorp lab, with no links to any other machines."

"Well, it obviously figured a way out. Why didn't you just erase it?"

Dad points at the Humvee that's leading the convoy. "Peterson wouldn't let me. The Department of Defense thought it could turn the program into a weapon. And they knew that researchers in other countries were doing similar work with artificial intelligence and neuromorphic circuitry." He lowers his voice, even though no one can overhear us. "A few months after we developed Sigma, Peterson showed me a classified report about a project in China. A Singularity-level AI had apparently infected the computers at an engineering complex in Tianjin. The Chinese army had to destroy the building to prevent the AI from escaping."

I shake my head, astounded. "And Peterson still wouldn't let you erase Sigma?"

"The Defense Department knew it couldn't stop all the AI projects around the world. There were too many of them, and some were in places like Russia and North Korea, where the U.S. military couldn't go. We just had to accept the fact that sooner or later a Singularity-level program was going to escape from a lab somewhere. And the worst thing was, we had no idea what the consequences would be. The AI might pose no danger at all. It might harmlessly bounce around the Internet, observing everything but doing nothing. Or it might even be friendly. It might help us cure cancer or eradicate poverty."

"Or it could be unfriendly," I point out. "It might set off explosions and electrocute people."

Dad bites his lip. "Yes, exactly. So Peterson gave me a new assignment. He asked me to predict what an AI like Sigma would do. And try to figure out how to make it friendly."

"By rewriting the program, you mean? Writing ethical rules into its code? Don't kill, don't lie, that kind of thing?"

"That's the first thing we tried on Sigma. But a Singularity-level AI has full control of its software code, so it can reverse any changes it doesn't like. We tried all sorts of programming tricks, but nothing worked. Sigma is like a human that way. You can't just cram something down its throat."

"So what did you do?"

"I convinced Peterson to try something else. The Pioneer Project."

I clench my good hand, steeling myself. "Why did you bring me here, Dad? And all the other kids too?"

He takes a deep breath. "Before I say anything else, I want to tell you how sorry I am. I just couldn't accept what happened when you got sick. That's why I started doing AI research. That's why I've pursued it for the past ten years. I wasn't doing it for Unicorp or the Army. I was doing it for you."

I don't understand. "Dad, what-"

"It has to do with the nature of the Singularity. It's not just about machines becoming smarter than humans. It's also about humans moving past their limitations. Becoming greater than their ordinary selves, transcending their ordinary lives. And as I thought about all the things that would become possible, I saw a way to save you." Dad's voice is weirdly high and choked. I think he's trying not to cry. "The Pioneer Project turned my idea into reality. The Army gave me all the money and manpower I needed. But I didn't have enough time to test it. I'm still not sure if it'll work."

I'm so confused. I feel like crying myself. "I thought this was about Sigma."

"It's more than that. It's-"

Dad interrupts himself by slamming on the brakes. I look ahead and see the cars in front of us stopping at a checkpoint. A newly constructed guardhouse, still unpainted, sits beside the highway, and a dozen soldiers stand in front of a chain-link gate that blocks the road. The soldiers wear winter-camouflage uniforms, dappled with patches of white and gray. Each man carries a sleek, black rifle.

"Whoa," Dad says, squinting at the guardhouse. "This wasn't here before."

"Is this the entrance to the Nanotechnology Institute?"

"No, we're still five miles away. It looks like the Army beefed up security."

I lean forward to get a better view. The soldiers in the Humvee at the front of the convoy step out of their vehicle and huddle with the soldiers at the gate. Colonel Peterson gets out of the Humvee too and shakes hands with one of the men, a tall soldier with broad shoulders and snow-white hair. This guy has three stars on his uniform, so he must be a general or something. Standing next to him, Peterson looks like a midget.

After a while several lower-ranking soldiers break out of the huddle and jog down the line of SUVs. They stop beside our car and one of them taps the driver-side window. "Mr. Armstrong?" the soldier shouts.

Dad rolls down the window. "Yes?"

"Please come with me to the Humvee, sir. General Hawke wants to have a word with you while we drive to the institute."

Frowning, Dad points at me. "I'm with my son. Tell Hawke I'll talk with him later."

"Sir, the general wishes to speak to you immediately. Another soldier will drive this vehicle the rest of the way."

Dad glares at the man. "I made an arrangement with Peterson. He said we-"

"I'm sorry for the misunderstanding, sir, but Colonel Peterson isn't the commander of this base. General Hawke is."

For a second I think Dad's going to curse the guy out. But instead he sighs unhappily and opens the driver-side door. He looks at me over his shoulder. "Don't worry. I'll see you when we get there." Then he steps out of the car and walks with the soldier to the front of the convoy.

My new driver, a beefy corporal with the name "Williams" on his uniform, takes Dad's place. He doesn't look at me or say a word. A moment later, the soldiers at the checkpoint open the gate and the convoy moves on.

Past the checkpoint, the ravine narrows. Treeless, snow-covered slopes loom over the road. My pulse races because I'm a bit claustrophobic. I feel boxed in by the mountains. But I'm determined not to show any signs of weakness in front of Corporal Williams, so I bite the inside of my cheek and stare straight ahead.

After several minutes we come around a bend and I see a sheer wall of rock in front of us. We're in a box canyon, bordered on three sides by high cliffs. The only way out is the way we came in. But as we approach the canyon's dead end I see another guardhouse and a dark, round hole carved into the rock wall. It's the entrance to a tunnel.

There are more soldiers at this checkpoint, but the gate in front of the tunnel stands wide open. General Hawke must've radioed ahead to let them know we were coming. The convoy rumbles into the tunnel, which goes on for several hundred yards. At the other end we emerge on a bare, flat basin, about a mile across, encircled by steep mountain ridges. Crusted with snow and ice, the ridges form a high, unbroken wall around the basin. It's like a giant bowl with a flat, muddy bottom.