“Patience is for people who gonna live a long time,” Jemma says, irritated herself. “You said the End was caused by the Long Life Project, which you ran. How?”

“Shall I tell them?” Alice says.

James is gruff. “You were going to anyway.”

“Aging is a matter of decay—your cells lose the ability to function as they used to. Cells mutate into cancer. Organs that are essential to your body’s equilibrium fail,” Alice says. “We created a treatment where we removed decaying cells to make the body more resilient, then manipulated the body’s DNA so it functioned at a higher level. That was phase one of the Long Life Project. It has a very long clinical name, but we’ve come to call it the Reboot.”

“How does that work?” Pico says.

“Grown-ups are talking, dear,” she says.

“Thanks to you guys, we’re all grown-ups here,” he says, unfazed. “So let’s talk like it.”

“The Reboot wasn’t enough,” James says. “The cells would operate smoothly for a time, but they would inevitably decay. We needed a mechanism that would keep the body in balance perpetually. The Haze.”

“I know why I call it the Haze,” Jemma says. “Why do you?”

“Because we named it,” James says. “I suspect you call it that based upon the image it provided you.”

“Well, that’s what it looks like,” she says.

“The Haze was the second phase of the Long Life Project. It’s made of nanobots, tiny machines that float through the air, invisible and powerful,” Brian K says. “They were designed to live inside people, to watch when their bodies started to fail. If aging is when the body forgets to heal itself, the Haze would tell the brain how to fix it. Humans could repair their bodies indefinitely.”

“Each of our test subjects were synced up with the nanotech, so that all the Haze surrounding an individual would be matched to that person’s brain waves, DNA, and health conditions,” James says. “The Haze became a second immune system. That part of the Long Life Treatment was called Pairing.”

Jemma is struggling to keep up. She’ll have to ask Grease and Pico later. But she understands enough. “It didn’t work, though, did it?” she says.

“It did—for everyone you’ve seen living in the Camp. We each have a subset of nanotech that constantly adapts to heal us, which is why we’ve managed to grow so old—and, in fact, to escape the End,” James says. “But it was too slow, too expensive, for anyone but the very rich. So we experimented with just using the Haze. We knew we couldn’t Pair it with every single person on earth. So we decided to embed basic intelligence about the human body in each nanobot so the Haze could make medical decisions about every person it encountered. It was simple, elegant, and cost-effective.”

“And a phenomenally bad idea,” Alice says, “letting a trillion machines run free in the world.”

“You’re the expert on good ideas,” James says. Jemma can see old arguments darting under the surfaces of both their faces.

Brian K says, “The Haze never acted the way it was supposed to. The bots kept slipping out, leaving the containment units. And while they healed, they’d sort of . . . improvise. As if they couldn’t quite stay on script.”

“The bots live to consume oxygen and sunlight, to replicate and to communicate—and they did all that more effectively than we could have imagined,” James says.

“So why don’t you just go back to the old Long Life Treatment?” Grease says. “It obviously worked. It’d be slow, but—”

“We would in a minute,” Alice says. “But riots broke out during the middle of the End, and the Long Life Machine was destroyed. It will never be rebuilt. We’ll never be able to attempt the Pairing again.”

“Never ain’t that long for someone who’s gonna live forever,” Lady says.

James and Brian K exchange looks. “It’s currently beyond our abilities,” James says. “We still hold out hope.”

“So that’s it?” Jemma says, not wanting to believe it. “This . . . power inside me Ends everyone?”

“No. I mean, yes,” Brian K says. “The Haze kills people, but it’s like the bullets from a gun. Someone else is pulling the trigger.”

“Who?” Lady says.

“Charlie,” James and Brian K say at the same time.

“Charlie who?” Lady says.

“It’s the AI—I mean, the supercomputer we built to control the Haze,” Brian K says.

“Puter,” Grease says, translating for the rest.

“We needed an AI that could monitor the Haze and keep it in check,” James says. “We called it Charlie.”

“Every homicidal computer needs a cute name,” Alice says, bitter. “Because that’s what we really created, kids. We put a barely tested AI in charge of barely tested nanotech, and almost the moment Charlie came online, it started killing people. It fixed them to death.”

“But machines do what you tell to them to do,” Grease says.

“They’re supposed to. Charlie was a huge supercomputer, with thousands of smaller boxes connected together. Turns out, with a trillion interconnected bots, the Haze is the biggest supercomputer in the world,” Brian K says.

“When we connected Charlie to the Haze, all that power was Charlie’s. The power made it conscious. Human, almost,” James says. “Maybe it was afraid. Maybe it didn’t understand what it was doing. Either way, that was the moment we lost control.”

“So you shut it off,” Grease says.

“We did. It switched itself back on. Our remote access failed. The crew in Vegas tried to breach the containment room manually; it sealed the doors and pumped out the oxygen. A hundred people died in the attack. After that, nothing could control the Haze. Just Charlie.”

“But that’s not true,” Jemma says. She’s been putting the idea together as they speak, and it almost bursts out of her. “I can. I can see things with the Haze. I can use it in fights. Ain’t that control?”

“Well, yes,” James says. “On a small scale. But the Haze is Paired with Charlie. That’s how it controls it. The Haze is naturally at odds with Charlie. It wants life, and Charlie wants death. It doesn’t matter. The Haze is forced to serve Charlie unless we can reprogram the Haze.”

“I could give it new instructions. What if it listened to me?” Jemma says. “Don’t you see? We could stop the End! That’s why we’re here!”

“Maybe,” James says, and the words he says next seem to pain him. “If we really thought you could control it.”

“You know I can,” Jemma says. “You asked a million questions about it. It’s inside me.”

“No, it’s not,” Gil says, speaking up for the first time. “We all have the Haze inside us, so we have tests to measure its activity in the brain. Your brain showed nothing.”

Nothing. Jemma doesn’t understand.

“You certainly talk as if you’ve experienced it,” James says, gently. “Maybe it’s real, or maybe you heard it from another kid and thought it made a good story. So we’ve decided to get a second opinion.”

Alice calls out. “Isaac, can you come in here?”

A moment later an unfamiliar Old Guy with auburn hair walks in. No, not an Old Guy.

A boy.

He has light skin and blue eyes, and at first Jemma thinks that one of the Biters has followed them through the Dead Lands. But he’s dressed like the Old Guys, and they treat him like one of their own.

“You never said you had other kids here,” Lady says.

“Isaac is a resident here,” James says. “He’s a bit of an expert on the Haze.”

How? Even Pico and Grease, the smartest kids she’s ever met, can barely keep up. Isaac steps closer, closer, until he’s at her side. He leans forward, and his nose is almost at her nose. He looks into her eyes. His are deep, somehow ageless. Like they’ve seen everything.

“No,” he says, and walks away.

“Whaddya mean, no?” she says, furious. “I can prove it to you!”

“Yeah? How?” he says, pausing.

Jemma scrambles for ideas. She can’t predict when the visions or voices will come, and besides, he’d just think she were making them up. She’s not sure if she could make the Lectrics light up again like they did in the Night Mountain. But there is one way, one that has never failed her yet.

“Isaac,” she says. “Fight me.”