The wind was muted now - she was inside a thin bubble of calm surrounding the train, like the eye of a hurricane.

Aya demagnetized her left crash bracelet, then slowly slid her hand across the board's grippy surface to the roof of the train.

It smacked down hard and secure.

But it was nervous-making, disconnecting her other crash bracelet. The hoverboard was Aya-size, the mag-lev inhumanly huge and powerful. She was like a rat hitching a ride on a stampeding dinosaur.

Shutting her eyes, she pulled her right hand free, then hauled herself up onto the roof and slapped her wrist down.

She'd done it! The tram rumbled below her like an unsettled volcano, and the half-muted wind still tore at her hair and clothes. But Aya was onboard.

The humming rose up around her - the train's smart-matter joints pulling it back straight. She'd made it just in time.

The train's roof stretched out dead straight ahead of her, dotted with nine Sly Girls along its length. Glancing back, the wind whipping handfuls of hair into her mouth, she saw the other three - everyone had made it.

The wind built as the train accelerated, and most of them were already surfing, standing with their arms out to catch the wind. Just like flying, Eden had said.

Aya sighed - as if riding on top of a mag-lev wasn't risky enough without standing up!

But if the Girls were going to accept her, she'd have to be as crazy as they were. And it wasn't really surfing if you were lying down.

She unthreaded the straps on her right bracelet, pulled it off, and curled up to wrestle it over her foot. It was all very clumsy, but after a minute's fumbling, she had the bracelet strapped tightly around her ankle.

She magnetized it, and felt her shoe plant hard against the metal roof.

Gingerly she released her other wrist...the wind didn't whip her away.

Time for the scary part.

Aya pushed herself up gradually, feet planted wide apart and arms out, like a littlie standing on a hoverboard for the first time. Up ahead, Miki's body was angled sideways into the wind, like a fencer presenting the smallest possible target. Aya imitated her as she stood up.

The higher she got, the fiercer the wind grew. Invisible, chaotic whirlwinds buffeted her body, twisting her hair into knots.

But finally Aya was fully upright, every muscle straining.

All around her, the world was a wild blur.

The train had reached the outer edge of the new expansion, where the city grew every day.

Banks of work-lights shot past like bright orange comets, earthmovers the size of mansions flitting by.

The wild lay just ahead, its dark mass the only steady shape in the maelstrom of lights and noise and rushing wind.

Then the last glow of construction streaked past, and the train plunged into a sea of darkness. As the city network fell behind, Aya's skintenna lost its connection with the city interface. The world was quickly emptied: no feeds, no face ranks, no fame.

As if the screaming wind had stripped everything away.

But somehow Aya didn't miss it all - she was laughing. She felt huge and unstoppable, like a littlie on horseback galloping at breakneck speed.

The train's awesome power flowed across her hands. Angling her palms flat, she felt the airstream lift her up, pulling her against the straps around her ankle, like a bird straining to fly. Every gesture whipped her body into a new stance, as if the wind was an extension of her will.

But just ahead, Miki's dark outline was crouching. Something was in her hand...

A yellow light.

"Crap!" Aya angled her palms down and bent her knees.

As she crumpled to the train's roof, something huge and invisible sliced the air overhead, hissing like the blade of a sword whipping past. Its shock wave rang through her body like a blow.

Then it was gone. Aya hadn't even seen what it was.

She swallowed, squinting into the wind. Ahead, a string of yellow lights stretched away toward the front of the train. They flicked off one by one, the danger past.

How had she missed them?

"Don't get too excited," Jai had warned. "Or you'll lose your head."

Trembling, she rose slowly from her crouch, her momentary sense of giddy power vanished. The darkness stretched out ahead as far as she could see.

Suddenly Aya Fuse felt very small.

TUNNEL

There were four things Aya was realizing about the wild.

It was formless. The forest rushing by on either side blurred into one impenetrable mass, a roiling void of speed.

It was endless, or maybe time had broken. Whether she'd been surfing for minutes or hours, she had no idea.

Third, the wild had a huge sky, which didn't make sense - it seemed like the sky would be the same size everywhere. But the blackness overhead sprawled out - unmarked by the city's jagged skyline, unstained by reflected light -  starlit and vast.

And lastly, it was cold. Though that was probably thanks to the three-hundred-klick wind in Aya's face.

Next time, she was bringing two jackets.

Some time later, Aya saw Miki's outline drop into a crouch. She looked worriedly at the other girls ahead, but no decapitation warning lights were showing.

Miki seemed to be playing with the bracelet around her ankle - then suddenly she was untethered, sliding backward across the train's roof on the seat of her pants, carried by the fierce headwind.

"Miki!" Aya screamed, kneeling and sticking out a hand.

As she slid within Aya's reach, Miki slammed a crash bracelet down, spinning to a halt. She was laughing, the wind whipping her hair in a frenzy around her head.

"Hey, Aya-chan!" she shouted. "How's it going?"

Aya pulled her hand back. "You scared me!"

"Sorry." Miki shrugged. "The wind always carries you straight down the train. Enjoying yourself?"

Aya took a deep breath. "Sure. But it's kind of icicle-making."

"No kidding." Miki pulled her standard-requisition shirt up, revealing Rangers' silks. "These work, though."

Aya rubbed her hands together, wishing Jai had warned her about the cold.

"I came back because we're almost in the mountains," Miki shouted, rising to one knee. "That's where the train slows down again."

"And we jump off?"

"Yeah. But the tunnel comes first."

"Oh, right." Aya shivered. "The red-light warning. I almost missed that first yellow."

"Don't worry. It's hard for a mountain to sneak up on you." Miki put her arm around Aya. "And it's not as windy in there."

Aya shivered, huddling closer. "Can't wait."

The mountain range rose slowly from the horizon, black outlines against the starlit sky.

As they grew nearer, Aya realized how big the mountains were. The one straight ahead looked wider across than the city's soccer stadium, and much taller than the central tower in town. It ate the sky as they approached, like a wall of blackness rolling toward them.

By now Aya was getting used to the unexpected size of everything out here. She wondered how anyone had managed to cross the wild back in pre-Rusty days, before mag-levs or hoverboards or even groundcars. The scale was enough to drive anyone crazy.

No wonder the Rusties had tried to pave it over.

"Here we go," Miki said, pointing.

At the front of the train, a red light was flickering. Another appeared behind it, a string of seven more igniting like a chain of sparklers.

Miki pulled a flashlight from her pocket and flicked it on. She twisted it to red, then waved it toward the tail of the train.

Aya was already unlacing the bracelet from her ankle. She wanted both wrists magnetized by the time they reached the tunnel.

"You okay?" Miki asked. "You look funny."

"I'm fine." Aya shivered. Suddenly she felt small again, the way she had after the train had first plunged into the wild.

"It's okay if you're not sure yet," Miki said. "I don't just surf because it's fun, you know? It also changes me. And that part takes a while to settle in."

Aya shook her head. She hadn't meant to sound unenthusiastic. The Sly Girls had to believe she was one of them, that she'd embraced their insanity keenly enough to give up kicking for good.

But it was true - something had shifted inside Aya, something she didn't quite understand yet.

The ride had whipped her so quickly from terror to elation, then just as suddenly to insignificance...

She stared out across the dark landscape, trying to untangle her emotions. This feeling was nothing like the obscurity-panic that consumed her when she saw the lights of the city, the horrible certainty that she would never be famous, that all those people would never care about her at all.

Somehow, staring into the darkness, she felt contented that the world was so much bigger than her. Overwhelmed, but calm.

"I know what you mean...it's sort of brain-shifting, being out here."

"Good." Miki smiled. "Now get your head down."

"Oh, right. Tunnel."

They lay flat on the train, snapping their crash bracelets down hard. The mountain grew closer and closer, until it towered over them like a huge wave rolling out of a black sea.

Squinting ahead, Aya watched the red warning lights disappearing one by one, gobbled by the tunnel's maw along with the front half of the train.

Then, with a vast shudder of the air, darkness swallowed them. The roar of the train redoubled with echoes and reverberations. Aya's whole body felt the difference in the train's vibrations.

The tunnel's blackness was a hundred times heavier than the starlight outside, but Aya could feel the tunnel roof sliding past - close enough to reach up and touch, if she wanted to lose a hand.

She felt the megatons of rock overhead pressing down, an infinite mass, as if the sky had turned to stone. Seconds ago the mag-lev had seemed huge, but instantly the mountain had dwarfed it, squashing her into the narrow sliver of space between the two.

"Do you feel that?" Miki called.

Aya turned her head. "What?"

"I think we're slowing down."

"Already?" Aya frowned. "Isn't the bend on the other side of the tunnel?"

"It is. But listen."

Aya focused on the tumultuous roar around them. Gradually her ears began to tease apart the sounds. The rumble of the train had a rhythm inside it, the steady beat of some imperfection in the track.

And that beat was slowing down.

"You're right. Does the train ever stop in here?"

"Not that I ever heard. Whoa! Feel that?"

"Um, yeah." Aya's body was sliding forward; the train was braking faster now. Her feet spun in a half circle around the bracelets, carried by her own momentum.

The roar and rumble died slowly around them, the train gliding to a graceful, silent stop. The stillness sent tremors across Aya's wind-burned skin.

"Something must have gone wrong with the train," Miki said softly. "Hope they get it fixed fast."

"I thought cargo trains didn't have crews."

"Some do." Miki let out a slow breath. "I guess we wait and - "

A light glimmered across the tunnel roof. It came from the right side of the train, flickering unsteadily, like a carried flashlight. For the first time, Aya saw the inside of the tunnel, a smooth cylinder of stone wrapped around the train. The roof was perhaps twenty centimeters from her head. She reached up and touched the cold stone.

"Crap!" Miki hissed. "Our boards!"

Aya swallowed. The hoverboards were still clinging to the right side of the tram, a few meters above head height. If whoever was out there looked up and saw one, they'd definitely wonder what it was.

"Let's see what's going on," Miki whispered. She unlocked her wrists and pulled herself toward the roof's edge.

Aya released her bracelets and crawled after Miki. If the hoverboards had been spotted, they had to warn the others right away.