David

A few hours later, a pile of scrap metal stood in one corner of the clearing. Each segment of rail took an hour to get free, and required all six of them to carry. The railroad ties sat in another pile; at least all the Smokies' wood didn't come from live trees. Tally couldn't believe how much they had salvaged, literally tearing the track from the forest's grasp.

She also couldn't believe her hands. They were red and raw, screaming with pain and covered with blisters.

"Looks pretty bad," David said, glancing over Tally's shoulder as she stared at them in amazement.

"Feelspretty bad," she said. "But I didn't notice until just now."

David laughed. "Hard work's a good distraction. But maybe you should take a break. I was just about to scout up the line for another spot to salvage. Want to come?"

"Sure," she said gratefully. The thought of picking up the powerjack again made her hands throb.

Leaving the others at the clearing, they hoverboarded up and over the gnarled trees, following the barely visible track below into dense forest. David rode low in the canopy, gracefully avoiding branches and vines as if this were a familiar slalom course. Tally noticed that, like his shoes, his clothes wereall handmade. City clothing only used seams and stitching for decoration, but David's jacket seemed to be cut together from a dozen patches of leather, all different shades and shapes. Its patchwork appearance reminded her of Frankenstein's monster, which led to a terrible thought.

What if it were made ofreal leather, like in the olden days? Skins.

She shuddered. He couldn't be wearing a bunch of dead animals. They weren't savages here. And she had to admit that the coat fit him well, the leather following the line of his shoulders like an old friend. And it fended off the whips of branches better than her microfiber dorm jacket.

David slowed as they came into a clearing, and Tally saw that they had reached a wall of solid rock.

"That's weird," she said. The railroad track seemed to plunge straight into the mountain, disappearing into a pile of boulders.

"The Rusties were serious about straight lines," David said. "When they built rails, they didn't like to go around stuff."

"So they just wentthrough ?"

David nodded. "Yeah. This used to be a tunnel, cut right into the mountain. It must have collapsed sometime after the Rusty panic."

"Do you think there was anyone...inside? When it happened, I mean."

"Probably not. But you never know. There could be a whole trainload of Rusty skeletons in there."

Tally swallowed, trying to imagine whatever was in there, flattened and buried for centuries in the dark.

"The forest's a lot clearer around here," David said. "Easier to work through. I'm just worried about these boulders collapsing if we start prying rails up."

"They look pretty solid."

"Oh, yeah? Check this out," David said. He stepped off his board onto a boulder, and deftly climbed to a spot that lay shadowed in the setting sun.

Tally angled her board closer and jumped onto a large rock next to David. When her eyes adjusted to the darkness, she saw that a long space extended back between the boulders. David crawled inside, his feet disappearing into the darkness.

"Come on," his voice called.

"Um, there isn't really a trainload of dead Rusties in there, right?"

"Not that I've found. But today might be our lucky day."

Tally rolled her eyes and lowered herself onto her belly. She crawled inside, the cool weight of the rocks settling over her.

A light flicked on ahead. She could see David sitting up in a small space, a flashlight glowing in his hand.

She pulled herself in and took a seat next to him on a flat bit of rock. Giant shapes were stacked above them. "So the tunnel didn't collapse completely."

"Not at all. The rock cracked into pieces, some big and some small." David pointed the flashlight down through a chink between where they sat. Tally squinted into the darkness and saw a much bigger open space below. A glint of metal revealed a segment of track.

"Just think. If we could get down there," David said, "we wouldn't have to pull up all those vines. All that track just waiting for us."

"Just a hundred tons of rock in the way, is all."

He nodded. "Yeah, but it would be worth it." He pointed the flashlight upward at his face, making himself hideous. "No one's been down there for hundreds of years."

"Great." Tally's skin tingled, her eyes picking out the dark fissures all around them. Maybe no human beings had been there for a long time, but lots of things liked to live in cool, dark caves.

"I keep thinking," David said, "the whole thing might tumble open if we could just move the exact right boulder...."

"And not the exact wrong one, the one that makes the whole thing crush us?"

David laughed and pointed the flashlight so that it lit her face rather than his. "I thought you might say that."

Tally peered through the darkness, trying to make out his expression. "What do you mean?"

"I can see that you're struggling with this."

"Struggling? With what?"

"Being here in the Smoke. You're not sure about it all."

Tally's skin tingled again, but not from the thought of snakes or bats or long-dead Rusties. She wondered if David had somehow already figured out she was a spy. "No, I guess I'm not sure," she said evenly.

She caught a glimmer of reflected light from David's eyes as he nodded. "That's good. You take this seriously. A lot of kids come out here and think it's all fun and games."

"I don't think that for a minute," she said softly.

"I can tell. It's not just a trick to you, like it is to most runaways. Even Shay, who really believes the operation is wrong, doesn't get how deadly serious the Smoke is."

Tally didn't say anything.

After a long moment of silence in the dark, David continued. "It's dangerous out here. The cities are like these boulders. They may seem solid, but if you start messing with them, the whole pile could crumble."

"I think I know what you mean," Tally said. Since the day she'd gone to get her operation, she'd felt the massive weight of the city looming over her, and had learned firsthand how much places like the Smoke threatened people like Dr. Cable. "But I don't really understand why they care so much about you guys."

"It's a long story. But part of it is..."

She waited for a moment before saying, "Is what?"

"Well, this is a secret. I don't usually tell people until they've been here for a while. Years. But you seem...serious enough to handle it."

"You can trust me," Tally said, then immediately wondered why. She was a spy, an infiltrator. She was the last person David should trust.

"I hope I can, Tally," he said, reaching out to her. "Feel the palm of my hand."

She took it, running her fingers over the flesh. It was as rough as the wood grain of the table in the dining hall, the skin along his thumb as hard and dry as leather cracking with age. No wonder he could work all day and not complain. "Wow. How long does it take to get calluses like that?"

"About eighteen years."

"About...?" She stopped in disbelief, then compared the horn of his palm with her own tender, blistered flesh. Tally could feel it there, the grueling afternoon of real work she'd put in today, but stretched across a lifetime. "But how?"

"I'm not a runaway, Tally."

"I don't understand."

"My parents were runaways, not me."

"Oh." She felt stupid now, but it had never once occurred to her. If you could live in the Smoke, you could raise children here too. But she hadn't seen any littlies. And the whole place seemed so tenuous, so temporary. It would be like having a child on a camping trip. "How did they manage? Without any doctors, I mean."

"They are doctors."

"Huh. But...hang on. Doctors? How old were they when they ran away?"

"Old enough. They weren't uglies anymore. I think it's called being a middle pretty?"

"Yeah, at least." New pretties worked or studied, if they wanted to, but few people got serious about a profession until their middle years. "Wait. What do you mean theyweren't uglies?"

"They weren't. But they are now."

Tally tried to get her mind to process his words. "You mean, they never did the third operation? They still look middle, even though they're crumblies?"

"No, Tally. I told you: They're doctors."

A shock ran through her. This was more stunning than the felled trees or the cruel pretties; as overwhelming as anything she'd felt since Peris had gone away."They reversed the operation?"

"Yes."

"They cut each other? Out here in the wild? To make themselves..." Her throat closed on the word, as if she was going to gag.

"No. They didn't use surgery."

Suddenly the dark cave seemed to be crushing her, squeezing the air from her chest. Tally forced herself to breathe.

David pulled his hand away, and with a corner of her panicked mind Tally realized she'd held on to it all that time.

"I shouldn't have told you all this."

"No, David, I'm sorry. I didn't mean to get all hyperventilated."

"It's my fault. You just got here, and I dumped all this on you."

"But I do want you to..." - she fought saying it, but lost - "to trust me. To tell me this stuff. I do take it seriously." That much was true.

"Sure, Tally. But maybe that's enough for now. We should get back." He turned and crawled toward the sunlight.

As she followed, Tally thought of what David had said about the boulders. However massive, they were ready to topple if you pushed them the wrong way. Ready to crush you.

She felt the pendant swinging from her neck, a tiny but insistent pull. Dr. Cable would be impatient by now, waiting for the signal. But David's revelation had suddenly made everything much more complicated. The Smoke wasn't just a hideout for assorted runaways, she realized now. It was a real town, a city in its own right. If Tally activated the tracker, it wouldn't just mean the end of Shay's big adventure. It would be David's home taken from him, his wholelife stripped away.

Tally felt the weight of the mountain pressing down upon her, and found that she was still struggling to breathe as she pulled herself out into the sunlight.