"Hey, Aya," Hiro whispered. "Remember that really boring story you kicked about recycling a year ago?"

"Yeah." Aya's nose caught a smell like approaching rain. "Those must be nanos - like smart matter, but not as smart. You can purify old steel with them, or combine it into stronger alloys."

"Nanos can also eat whole buildings if you're not careful," Hiro said. "That's why they're working in a pit, in case they get out of control."

"So the freaks could use nanos as weapons, right?" Aya said.

Hiro snorted. "Whatever makes my little sister happy."

"I'm just saying, they're not exactly making sushi down there," she mumbled. "I hope you're getting some shots, Moggle."

The inhuman air-swam toward a rusted girder that a lifting drone had just dragged in. He gave it a spray of the silvery nanos, and another wave of heat billowed from the tent.

The drone glided away from the wriggling mass, heading toward the pile of scrap that had already been treated. The bubbling nanos were gradually subsiding, leaving a shiny lump of steel. The drone closed its huge fingers around the metal and dragged it out of the tent.

"Let's see what happens next," Hiro said.

Beneath the next tent was another pit, a pile of purified steel lumps at one end. At the other sat a dozen curved shapes made of thin, crisscrossing lines, like skeletons made of wire.

"Nano-frames," Hiro said.

Aya nodded. "Those were in your hole-in-the-wall story, right?"

"Yeah, but I kicked that ages ago." He paused for a second, and they watched a lifting drone drag a lump of metal across the pit. Another hovering inhuman guided its progress, making gestures with his fingers.

"That looks like fun," Aya said, glancing over her shoulder to make sure Moggle was shooting.

"See how that drone follows whatever his hand does?"

The nano-frame was glowing now, turning bright white. It was about fifteen meters long, with swelling curves like the hull of a boat.

"Nano-frames are the patterns inside holes in the wall," Hiro explained.

"Huh," Frizz said. "I always wondered about that."

The chunk of metal inside the nano-frame began to turn red, its edges softening like a melting ice cube's. A wave of heat spilled out from the tent.

Aya squinted, her eyes stinging. It felt like standing too close to a fire.

"Whoa," Frizz said. "How come my wall never gets this hot?"

"Because you never made anything that big," Hiro said.

The metal was moving now, flowing across the nanoframe like a viscous liquid, taking on its shape. It filled the spaces between the wires, like skin covering a skeleton. When it had stretched across the entire frame, the steel began to cool back into a solid. The inhuman was already guiding the lifting drone, nudging another lump of metal onto the next nano-frame.

"So here's a question," Frizz said. "What do all these shapes make when you put them together?"

Aya looked at the jumble of pieces. All were gently curved, but she couldn't figure out how they went together.

"They look like boat hulls," she said.

Hiro snorted. "Ah, the popular solid steel canoe."

"I said like boats," Aya said.

"There's no point guessing," Frizz said. "Let's keep moving till we get to the end."

The next tent was much larger, as wide as a soccer field.

The pit beneath it was at least forty meters deep, full of finished metal shapes and tangles of circuitry. Several inhumans floated inside, each manipulating a pair of hand-shaped lifting drones. The air was full of clanking and hissing as hot metal collided and fused.

As she crept along the tent, Aya saw how the system worked. Each inhuman added one new piece, then passed it down, hardly pausing before setting to work on the next.

"An assembly line," Frizz said. "Like an old Rusty factory."

"Except much bigger," Hiro said. "Thanks to those drone hands."

Aya nodded, remembering the Rusty term for this: mass production. Instead of making things only when people needed them, like holes in the wall did, Rusty factories had churned out vast quantities of stuff - t he whole world in a giant competition to use up resources as quickly as possible.

The first hundred years of mass production had created more widgets and toys than the rest of history put together, but had also covered the planet with junk and sucked its resources dry. Worse, it was the ultimate way to turn people into extras - sitting all day performing the same task again and again, each worker a minuscule part of the whole machine. Anonymous and invisible.

As they neared the end of the tent, the shape of the assembled pieces gradually became clear.

One finished piece stood there, almost as tall as the pit was deep, with curved sides swelling gently in the middle. It was sleek and aerodynamic, the top tapered to a sharp point. Flight control surfaces stuck out from its sides, like fins on a shark.

Aya remembered this history lesson too - no one could forget it - and realized that the inhumans'

plans didn't really need mass drivers, or smart matter, or anything more advanced than classic Rusty technology.

The awful thing that stood before her was a missile -  an old-fashioned city killer, pure and simple.

And every few minutes, another one was coming off the assembly line.

MISSILE

"Huh," Aya murmured. "I was actually right."

Hiro nodded slowly. "Somehow, I wish you weren't."

"But this doesn't make any sense," Frizz said. "Why build all those mass drivers and then use old-fashioned missiles?"

"Maybe chunks of falling steel weren't evil enough for them," Hiro said. "Think of all the stuff Rusty missiles carried. Nanos, bio-warfare bugs, even nukes."

Aya swallowed. "So this isn't about using up metal, or even knocking down a few cities. It's about ..."

"Killing everyone," Hiro finished.

"So they strip the ruins all over the world, shoot the metal here, then launch it right back at us?"

Frizz shook his head. "Isn't that a little complicated?"

"You heard Fausto," Hiro said. "The equator's the easiest place to launch from."

Aya nodded, feeling a wave of guilty relief. Her story was true, except she'd been too optimistic.

Nukes, nanos, bugs - whatever these missiles were carrying had to be a hundred times worse than falling metal.

"But it only took a single Rusty missile to kill a whole city," Frizz said. "Why are they building so many?"

"Humanity survived the oil plague," Aya said, shivering. "Maybe they want to make sure they kill everyone this time."

"We have to warn Tally," Hiro said.

"How?" Aya asked. "She's probably more than a kilometer away. And the freaks will catch us if we even try to ping her."

"Then we have to go back to the ruin, use that transmitter to kick this place to the whole world."

"But Tally said to wait!"

"She thought the freaks might be on her side," Hiro said. "But it looks like they're not on anyone's side."

Frizz shook his head. "But what if we're wrong? Do you want to make the same mistake twice, Aya?"

He was staring at her, Hiro too, like she was responsible for the whole world's safety. But it was still her story, she supposed. Right or wrong, history would remember Aya Fuse as the one who'd kicked it.

She sighed. "Okay. Before we do anything, let's make absolutely sure. We have to take a closer look."

Down in the pit, three lifting drones had gathered around the newly constructed missile.

Stretching out their metal fingers, they gently tipped it over onto its side, carrying it out of the factory and into the night.

Aya scanned the darkness, but saw nothing except for the crooked shapes of girders thrusting from the ground. "No one's around."

"Those drones must be automatic," Hiro said. His night-black hand stretched out a finger. "Look where they're headed."

In the distance was a taller building. A lot more solid than the tents, it was shrouded in darkness.

Hiro glided ahead, and Aya and Frizz took hold of Moggle. The hovercam towed them through the girders, staying low to the ground.

"It's kind of weird how few people we've seen," Frizz said.

"Mosquitoes, I guess," Aya said. "If we weren't in these suits, we'd have been eaten right now."

"Maybe so. But you'd think anyone planning to nuke the world wouldn't mind using a little bug spray."

Aya remembered what she'd seen from the hovercar -  lots of inhumans braving the wind and rain, pushing their way through the girders. But on this still night no one was outside. Were they all busy making weapons?

As they neared the darkened building, the lifting drones slowly angled the missile upright again.

Two huge doors swung open, revealing a vast space within. Orange worklights spilled out across the hard-packed dirt.

The drones carried the missile inside.

The three of them floated to the edge of the huge doorway and peered in.

"Nothing but a bunch of parts," Hiro said softly. "No people, as far as I can see."

The doors began to swing closed.

"What do we do?" Frizz asked.

"We have to get a closer look at that thing," Aya said. She crept along behind one slowly closing door, Frizz and Hiro following. They slipped inside just before the doors met, the boom echoing through the building.

"Great," Frizz whispered. "We're stuck in here now."

The missile stood before them, the three lifting drones still attached to it.

Dozens of tiny platforms hovered in the air, like serving drones at a party, but motionless. They carried instruments and tools, electronic parts, and objects that Aya found completely mysterious.

"Shoot those," she told Moggle.

"This must be the next step in the assembly line," Hiro said. "Where they do all the detailed work by hand."

"So where are they?" Frizz asked. "We haven't seen anyone since that last tent."

"I guess that's a little nervous-making," Hiro said.

A hissing noise filled the room.

Frizz nodded. "Definitely nervous-making."

Aya looked up - flakes were falling from the sky, like snow, but softly glowing. Near the ceiling a swarm of tiny drones hovered, spraying out gleaming white clouds.

She caught a snowflake, watching it melt into a softly glowing white spot on her palm. Through the sneak-suit glove, she couldn't tell if it was warm or cold.

"Maybe it's some kind of fire-fighting foam," Hiro said.

Aya frowned. "But nothing's on fire."

"Maybe they're really safety conscious," Hiro muttered.

"I don't think it's about safety," Frizz said. "Look at us!"

Aya turned to Frizz, and her eyes widened. Glowing spots had appeared all over his sneak suit.

She watched another flake hit his shoulder, melting into a soft white mark. Luminous flecks covered her own arms.

"You're both totally visible." Hiro looked down at himself. "Me too!"

Frizz shook his head. "They knew we were wearing sneak suits!"

"That means they know where we are..." Aya's voice faded. The three lifting drones had drifted away from the missile. They turned as one, floating closer through the air.

Their huge fingers were opening wide...

HANDS

"Moggle," Aya cried. "I need you!"

Hiro was already zooming toward the ceiling. One of the drones swerved to follow him, the other two coming straight for Aya and Frizz.

"Jump!" Frizz grabbed her hand and pushed off hard from the ground.