Aya watched her fall into the depths, hoping that Moggle had gone up rather than down...

Kai turned to her. "What were you and Miki chasing, anyway?"

Aya shrugged, which sent a twinge of pain through her shoulders.

"You okay?"

"I've been using my crash bracelets a lot tonight."

"I noticed that." Kai chuckled. "I knew you were one of us, Aya-chan."

"Thanks." Aya smiled weakly - another dizzy-making wave of exhaustion was hitting. "But maybe I'll rest a minute. My adrenaline needs a recharge."

"No problem." Kai leaned out to peer down the shaft and sighed. "This could take a while."

Aya crawled past the other Sly Girls in the tunnel, waving off their questions, saying she needed a rest. She climbed out and made her way through the cylinders and to the stairs. Halfway up, she crouched down, booting her eyescreen.

"Moggle?" she whispered.

The hovercam's point of view appeared against the darkness. It took Aya's tired brain a moment to adjust to infrared, but Moggle was looking down.

The cluster of body-heat blobs below were the Sly Girls crowded at the shaft's edge. Eden Maru was a pinprick of light farther down, the lifters of her hoverball rig shimmering against cold stone.

Moggle had lucked out so far. Of course, Eden would explore the upper part of the shaft eventually.

"Keep climbing," she whispered. "And look for a way out."

The sides of the shaft passed by unchanging - thick copper coils every meter or so, no way in or out. But a subtle infrared glow came from directly over Moggle, a sliver of heat at the top of the shaft.

"Find out what's up there. But don't use your night-lights!"

Aya dimmed her eyescreen for a moment, checking to make sure no one had followed her. The room full of cylinders was still empty.

As Moggle climbed, its signal began to fritz, shimmers of static dancing across her eyes. The connection was punching through a lot of stone, and Aya wondered how long the shaft was. Her skintenna could only reach a kilometer without the city network helping.

By the time Moggle reached the top, Aya could barely see through the clouds of interference.

The hovercam seemed to be in a transparent bubble; soft lights shone down through the rounded plastic walls.

They looked like...stars.

Aya moved a few steps up, and the static cleared for a moment. It was true: Moggle was looking out from the top of the mountain.

Suddenly the whole mountain range was laid out around her. Sharp peaks cut into the starry sky, and down in the valley the mag-lev's solar collectors glimmered with reflected starlight. Aya could even see the lights of the city glowing faintly in the distance.

But what was the point of carrying the cylinders up to the top of the mountain? There were simpler ways to move big hunks of metal, after all - lifting fans and heavy vehicles.

And why do it all from inside a mountain?

The signal fritzed again, and Aya shifted on the stairs until she found a better spot. When the image cleared, she frowned. Something glittered in the corner of her eye.

"Turn left a little, Moggle."

The view rotated to bring the mag-lev line in front of her, and Aya swallowed. The warning lights along the expanse of tracks were blinking...

Then she saw it in the distance, a string of lights crawling silently from the city. An unlikely, maybe-once-a-month, unscheduled train was headed toward the tunnel.

And Kai had left the hidden door wide open.

AIR PRESSURE

"Stay up there until I call you," she whispered. "But be ready to move!"

Aya ran down the stairs, wondering what would happen if the train shot past the open doorway.

Equipment and furniture were piled up around the entrance, along with a big stack of the Sly Girls'

hoverboards.

Aya had felt with her own body what the wake of a speeding mag-lev train could do.

She ran through the cylinders, her reflection a blur in their smooth metal sides, her mind spinning.

How was she supposed to explain how she knew a train was coming?

The mouth of the tunnel glowed with the Sly Girls' flashlights. They were sprawled around its entrance and down its length, crowding the narrow space.

"Out of my way!" She dove into the tunnel, crawling straight across the Girls, ignoring their annoyed shouts. "Everyone, listen! A train's coming!"

Silence fell, and Kai turned to peer at her. "What do you mean?"

"You know those unscheduled trains you weren't worried about? Well, one's headed toward us!

It'll be here in a few minutes!"

Kai narrowed her eyes. "What makes you think that?"

"I was heading back toward the main door ... to get a hoverboard. I thought maybe some of us could go down the shaft on one."

"You got all the way there and back in five minutes?"

"No...but halfway there I could feel the ground rumbling. Come on, Kai. We don't have time to lose!"

Kai hesitated, and a murmur of disbelief traveled through the tunnel.

Aya groaned, scrambling over more bodies and up to the edge of the shaft. ''Eden ... a train's coming!"

A few seconds later Eden Maru shot up into view. "A train? We didn't seal the door!"

"So what?" Kai said. "At that speed, who'll notice anything? Most mag-levs don't even have crews."

"But our boards! They'll get sucked into the slipstream, along with anything else that's not tied down!"

"And you didn't mention this before?" Kai cried.

"You said there wouldn't be any trains!"

"I said probably!"

"Just get out of my way!" Eden put her hands together like a diver, and shot down the crowded tunnel.

Instantly the narrow tunnel was full of scrambling bodies. The Sly Girls were shouting and shoving past one another, tumbling out to follow Eden back toward the entrance to the mountain.

Kai hesitated for a moment, her eyes fixed on Aya. "You sure you didn't just imagine this?"

Aya nodded, still breathless.

Kai swore and rose into a hall crouch, scrambling after the others.

Aya waited until the sounds of pursuit faded away, then booted her eyescreen again. She lay against the stone floor, staring straight up into the blackness of the shaft.

There was nothing but air between her and Moggle now, the view from the mountain top crystal clear. The train was much closer, a bright string of pearls crawling along the flashing mag-lev line, only minutes away.

"Get down here fast, Moggle!'' she said. "Don't hover -  just drop!"

Moggle angled its lenses downward, and Aya watched the fall from the hovercam's point of view. The hot yellow infrared speck of her own head grew, faster and faster as Moggle accelerated down the shaft, until she could see her own wide-eyed expression.

"Stop!" she shrieked.

The hovercam came to a perfect halt a few centimeters from her nose, and flashed its night-lights happily.

"Its nice to see you too. And ouch, blinded, etc." Aya scuttled down the narrow tunnel. "Follow me, but not too close. If we run into anyone else, remember to hide!"

Aya dashed through the stone warren of the hideout, following the metal studs back toward the entrance. That was how Moggle had found her, of course. Just like the cylinders, a hovercam could only travel along the metal path.

By the time she reached the main hallway Aya was breathless from running, her heart pounding.

Straight ahead, the crowd of Sly Girls was silhouetted by the entrance to the mag-lev tunnel.

Staggering to a halt, Aya felt the trains rumble beneath her feet.

''Any time now," Kai was saying.

"I'm trying!" Eden knelt by the doorway, the matter hacker clutched in one hand, the other flitting across its controls.

But the smart matter of the door wasn't moving.

Aya glanced over her shoulder and caught Moggle peeking out to get a shot. She smiled.

Whether the door closed or not, whatever happened next was going to be very kickable.

"Everyone get set," Eden said. "Just in case."

Ahead of her, the Sly Girls linked crash bracelets to form a human chain. Not that it would help - if this loose furniture and equipment started flying around, they were all in trouble anyway.

Finally Eden Maru let out a grunt of triumph. The smart matter was rippling to life, its black tendrils beginning to weave across the opening.

But the train was already in the tunnel - Aya could feel it, her ears popping as the air squeezed toward them at three hundred klicks an hour. The rainy scent of the changing smart matter washed over her.

The rumble was building quickly now, whirlwinds of dust spinning madly in flashlight beams. The first layer of the door had stretched across the entrance, but it bulged out toward Eden, like a toy balloon squeezed between two hands.

If the door blew out, Aya wondered what would happen to the train. Would the sudden change in pressure be enough to blow it off its tracks?

Next to the bulging expanse, Eden was still twisting at the hacker's controls, yelling something drowned out by the roar of the train.

More layers slid into place...

The thundering peaked, the piles of equipment all around Aya dancing across the floor. The smart-matter surface of the doorway was vibrating too fast to see, shimmering like a plucked guitar string.

After a long moment, the roar began to fade as the train slipped away.

The door hadn't collapsed; now that the train had passed, Aya couldn't even tell the smart matter apart from the stone.

As Eden slumped to the floor, Kai turned to the rest of them, a weary smile on her face. "Maybe that was enough fun for one night."

A tired murmur went through the others; maybe Aya wasn't the only one who'd gone sleep-missing the last couple of nights. The Sly Girls started sorting out their hoverboards, getting ready to head for home.

The only problem now was sneaking Moggle out.

"Hey, Kai," Aya called. "Can we borrow a few things?"

Kai looked around at the equipment cluttering the hall. "I suppose so. But don't make it too obvious someone's been here."

"In this mess?" Aya laughed. "They're stripping the place, not taking inventory."

Adding their assent, a few of the Sly Girls started poking through the equipment. With no face rank or merits, Aya realized, they couldn't do much requisitioning. The wallscreens and workstations lying around were tempting targets.

She walked quickly back to where Moggle was hiding, and picked a storage carton at random.

Dumping the contents out - light pens and drawing tablets - she waved the hovercam inside. The plastic top sealed with an airtight pop, hiding Moggle completely.

At a twist of her crash bracelets, Aya's hoverboard made its way down the hall to her. She pressed the container against its riding surface, and felt the snap of Moggle's lifters gripping through plastic.

She was ready to go, carrying one hovercam full of very kickable shots.

"Pretty tricky, you knowing that train was coming."

She looked up to find Eden Maru floating above her.

Aya shrugged. "Not what I'd call tricky. The floor was rumbling."

"Funny thing, though," Eden said. "When I first got here, I couldn't feel anything. Not till the train was much closer. But you noticed it from way back inside the mountain."

"Maybe it's that hoverball rig you're always wearing." Aya smiled. "You're not used to walking the Earth like us extras."

"Yeah, that must be it." Eden glanced down at Moggle's hiding place. "Find anything interesting?"

"Just light pens, stuff like that. Want one?"

Eden hesitated, then shook her head. "No thanks. I don't have to steal stuff. I'm famous, remember?"

"Sorry, I forgot."

Eden finally smiled. "Don't be sorry, Nosey-chan. It shows you're coming along."