She dropped to the snow and moved to the next truck. There were two more pupae inside. Each resting on the seat where the human host had died.

It was the same for the next ten vehicles she checked. Every seat filled. Everyone inside dead.

But some of the convoy's refugees, either trying to escape or maybe stepping outside to see why the convoy had stopped, had not been changed. They lay frozen on the ground, their still-human outlines barely visible beneath the layer of snow that had settled over them, a shroud of pure white. Some had not managed to make it any farther than their open doors and now lay face-down in the snow, their torsos covered by a white veil while their bottom halves remained inside their vehicles.

That was strange. It was as though the extra insulation provided by the closed-off vehicles had allowed the trans.m.u.tation to progress to its later stages, while for those who made it outside, the lower temperature had arrested the development into the alien pupa form.

It was only after Emily wiped a sheen of sweat from her forehead that she realized how warm it had become. She exhaled heavily. There was no white fog of breath. In fact, she could feel the air warming around her, tingling against her ears and her cheeks.

How could that be?

A minute or so later, as she checked for a clear route between a tanker and what looked to be a decommissioned school bus, she had to unzip her parka. The temperature must have risen at least three degrees in that time. She could feel a warm breeze blowing against her face and hands, like a car heater turned to low. It was sweeping down from the mountainside above her, and, as she looked up the mountain toward the peak, she could see rivulets of water beginning to run down the mountain as the snow began to melt.

She glanced around her at the maze of metal. It was thawing down here, too. The windshield of the school bus that had just a minute ago been covered in a crispy frost was now completely clear, exposing the dim outline of another pupa in the driver's seat. A continual drip, drip, drip of melting ice water ran off the hood.

Emily headed back to the waiting Cat.

There was a sudden loud crack like split wood off to her left.

She started at the noise. It had come from the inside of a Toyota SUV, stopped near the edge of the mountain pa.s.s. She paused, listening, then when the noise did not come again, crunched over to the Toyota. A large chunk of snow and ice that had collected on the roof slid off and fell to the ground as she approached.

Leaning in, Emily used the arm of her parka to wipe away the sheen of condensation that had collected on the pa.s.senger side window.

There was another pupa inside, but this one was open. A long fissure ran down the center of the sh.e.l.l; there was an inch of s.p.a.ce between each side. As she watched, a set of spindly black legs, each with a sharp claw at its tip, rose slowly from the darkness of the pupa's interior, grasped each side of the sh.e.l.l, and pushed them wider apart.

Emily took an involuntary step back. "You have got to be kidding me!" The pupae were still alive? They should be frozen solid.

She glanced back at the row of stalled vehicles. There could be hundreds of aliens gestating inside them, for all she knew, heated by the warm thermals sweeping down off the mountaintop.

"Great. Just freaking great," she spat as she began to make her way back to the Cat as quickly as she could. The top layer of snow was rapidly turning to slush beneath her feet. An occasional spindrift of white still leaped into the air, lifted by the warming breeze.

From all around her now, the cracks of splitting pupae began to resonate, bouncing off the sheer walls of the winding mountain road.

There was still sixty feet left between her and the Cat when Emily heard what sounded like a squadron of mosquitoes buzz into life. She glanced back in the direction of the metal graveyard. A blur of movement behind the windshield of the nearest big rig drew her eyes to it. There was a whirring motion, like a propeller of an airplane, then a screeching sound that was quickly followed by an almost perfect circle appearing against the windshield of the truck. Gla.s.s powder began to fly away from the windshield as the alien caught inside began to use its specialized mandibles to cut a way out.

Then the gla.s.s circle fell off, and Emily began to run.

She pa.s.sed the first jackknifed truck just as the alien inside was squeezing through the hole it had made in the pa.s.senger side window. Emily could see its black claws pushing through the opening as it pulled itself out onto the hood of the truck.

Rhiannon's shocked face, her eyes wide, mouth agape, pressed against the window of the Cat, staring at the alien as it emerged from the frozen tomb. At her side, Thor barked silently through the reinforced windshield.

The snow had become slippery, almost like mud now, and it sucked at her feet, slowing her pace. She was almost at the Cat's front set of tracks when the newborn alien launched itself into the air toward her from the side of the cab that still hung precariously over the precipice.

Emily let out a gasp as it landed on the lip of the road just a few feet from her, its two front claws furiously trying to find purchase on the slippery surface, while its back legs scrambled against empty air. It managed to hang there for a few seconds then, just as Emily clambered up onto the gantry of the Cat, she saw the creature lose its fight and disappear silently over the edge.

Emily pulled at the door, but it was still locked. She hammered furiously on the window until Rhiannon, still shocked at what she had just seen, reached across and flipped the lock. Emily pulled the door open and jumped inside, locking the door again behind her.

"What is that?" Rhiannon demanded.

Emily ignored the girl. As she repositioned herself into the driver's seat, she looked up at the convoy just in time to see the first wave of twenty or more spider-aliens begin to collect on the flat top of the lead big rig.

"Emily? What are they?" Rhiannon yelled again, almost in tears now.

"They're aliens, Rhiannon. And we have to get out of here, right now."

But where was she supposed to go? She couldn't go back, there was no other way across these mountains than the road they were on. They were still far too high up to try a direct descent over the side of the mountain; it was virtually a sheer drop all the way to the bottom at this point. There was only one way: forward, through the maze of stalled and wrecked vehicles.

More of the creatures had collected on the roof of the first rig, milling around aimlessly, scuttling back and forth as if looking for some way off the mountain.

Emily revved the engine and moved toward the s.p.a.ce at the back of the first rig, keeping the Cat moving as fast as she safely could. She edged around the back of the first trailer and aimed toward the second larger gap.

As she pa.s.sed the end of the trailer, something heavy hit the top of the Cat's roof.

Rhiannon squealed as first one, then a stream of the spider-aliens landed on the roof and then jumped down to the snow beside them. A constant stream of the creatures poured off Emily's side, hitting the snow, rolling, and righting themselves, then leaping and jumping as they hit the snow. It was almost as though the snow was burning them. Some of the creatures took off toward the nearest vehicle; others bounced like scalded cats until they either stopped moving or disappeared off the lip of the road.

As Emily finally cleared the first truck, the flow of aliens stopped, but not before one final creature launched itself off the top of the truck. It hit hard on the roof and bounced down onto the extended hood of the cab. It scrabbled around and clacked toward Emily and a screaming Rhiannon, smacking against the reinforced windshield. It clung there for a moment, each of its two eyestalks focusing on one of the humans inside the cab.

Thor's head appeared between the two seats, drool flying from his mouth as he snarled and barked at the unwanted hitchhiker.

The malamute's barking only grew more manic as the alien's bulbous black head reared back and the two cutting appendages that pa.s.sed for jaws suddenly began to spin furiously. In seconds they were nothing but a blur of motion. The creature's head dropped forward and connected with the windshield. Instantly the inside of the cabin was filled with a high-pitch whine, worse than a hundred sets of fingernails on a blackboard. A plume of pulverized gla.s.s flew from the junction of windshield and alien.

Emily's vision, already half-obstructed by the creature's huge corkscrew-like body, was blocked completely, her senses overwhelmed by the piercing screech of pulverizing gla.s.s.

She hit the brake rather than risk a collision.

A second later and a circle of gla.s.s fell away, crashing onto the dashboard. The reinforced gla.s.s of the windshield refused to shatter and fell to the floor. The creature eased its head through the newly opened s.p.a.ce, swiveling back and forth as if surveying the cab's interior. Its matte-black skin seemed to brighten as it touched the much warmer air of the Cat's cabin.

Rhiannon was screaming over and over, "Emily! Kill it. Kill it."

Thor was still trying, unsuccessfully, thank G.o.d, to push his way between the seats and reach the creature, which was already forcing itself through the portal it had created. Rhiannon had shrunk as far back into her seat as she could, trying to remain out of its reach.

"Thor. Get back," Emily screamed as she twisted around and pushed herself between the dog and the seats, reaching for the shotgun. "Get back, Thor," she yelled again when the dog continued to try to move forward. The dog finally acceded and wriggled free of the s.p.a.ce. It was all the room Emily needed, and her fingers found the strap of the shotgun.

She pulled the Mossberg toward her, grabbing it with both hands. Swinging around, she brought the gun down to her side, aiming the barrel at the creature's head.

It was halfway through the hole now, its eyestalks swiveling back and forth. Emily paused, her finger on the trigger. If she fired the gun in here, there was no telling what kind of damage the buckshot might do. It could ricochet around the cabin and maim her, Rhiannon, or Thor. The blast would surely kill the creature, but this close it meant an added danger from flying alien carca.s.s. She couldn't risk it.

Emily flipped the shotgun around and hit the creature between its two eyestalks with the b.u.t.t of the shotgun.

The eyestalks shrunk back, and the thing's buzz-saw jaws flew wide apart. It was, Emily supposed, the closest the alien could come to expressing surprise. But it didn't back away, so she hit it again, this time aiming for the top eyestalk. It exploded into a mess of black goo.

That seemed to get the message across that it was not welcome, and the thing rapidly pulled back through the hole, skittering off the hood of the Sno-Cat.

With the alien gone, the cabin was now replaced with the rumble of the idling engine flowing in through the hole in the windshield. She was going to have to figure out some way to fix that.

"It's the warmth of the cabin," Emily said with sudden realization, more to herself than Rhiannon. "These things are surrounded by snow and ice. They must be extremely sensitive to changes in temperature. That makes the inside of this cabin the f.u.c.king Ritz-Carlton for them."

Whatever weird weather anomaly had caused the sudden warming of the air outside had increased the ambient temperature on this side of the mountain enough to thaw the creatures out. Now they were instinctively looking for a way off the mountain. That meant Jacob's observation was only half-right. The cold only stopped the effects of the red rain. It was going to take prolonged exposure to frigid weather to have the same effect on the creatures as she had seen with the aliens at the playground, back in Fairbanks.

The thought had no sooner entered her mind than Rhiannon screamed a warning, "Look!"

Emily followed the girl's eyes. "Oh! s.h.i.t!" she hissed from lips that suddenly felt dry and cracked. Clambering over the sides of the big rig in front of them was another wave of spider-aliens. They leaped from the side of the rig, making a beeline for the stationary Cat, attracted by the plume of escaping warm air of the cabin.

Emily floored the accelerator, sending a spray of melting snow up from the tracks as the Cat began picking up speed. There were at least sixty of the little b.a.s.t.a.r.ds heading toward them, Emily estimated. There was no turning back now, though; she had to keep plowing forward. Aiming the front of the Cat toward a s.p.a.ce between the next two vehicles, Emily pushed the speed up to thirty-five.

"Hold on," she yelled at Rhiannon over the roaring engine just before the Cat hit the leading edge of the onrushing aliens.

There were several resounding thuds as the machine met the monsters. The thuds were quickly followed by a series of satisfying pops and crunches as the tracks of the Cat crushed the carapaces of the first few unlucky creatures.

More tried to leap onto the Cat as it rolled over them, but they either bounced harmlessly off the sides or were caught by the four tracks and crushed to a purple pulp. One did manage to land on the gantry running alongside Emily, but it skidded and slipped along the metal surface, unable to find purchase, before sliding off the opposite end.

And then they were through the creatures. Emily gunned the engine, pushing the Cat up to forty in an attempt to leave the creatures behind. She gained some distance, but the things were persistent little b.u.g.g.e.rs; she could see them streaming down the hill behind her even as the gap between them widened.

There was enough s.p.a.ce between the next few vehicles that Emily didn't need to slow down, and the distance between them and their pursuers grew even greater. One hundred, then two hundred, then three hundred feet separated them. But as she slowed the Cat to maneuver around a blind hairpin corner, she was forced to slam on the brakes again.

A truck, towing a thirty-foot flatbed, had come to a halt right at the apex of the turn; its cab took up the entirety of the center portion of the snow-covered road, leaving less than ten feet of s.p.a.ce separating it from the right edge. Beyond the edge, an almost sheer drop fell the final sixty feet or so to the plain below.

Emily stared back through the rear window toward the summit. The creatures were still doggedly following her, swarming down the mountainside.

There was no time to lose. She had to risk it.

Emily reversed the Cat back until she was as close to the edge as she dared.

"Rhiannon, I need you to be my eyes," Emily said, trying to keep the panic she felt from her voice. "Look out the window on your side and tell me how much s.p.a.ce there is between us and the edge, all right?" Rhiannon stared blankly at Emily for a second, then nodded and scooted over a little until she was pressed tightly against the door.

"How much, honey? Quickly." Emily could see the wave of creatures closing in on them in the side-view mirror.

Rhiannon turned and held her two hands up in the air to ill.u.s.trate the distance. "This much," she said. About ten inches. That gave Emily a little more room to edge over, just a couple of inches but no more. Rhiannon's face was almost as white as the snow, and Emily could see a vein twitching convulsively in her throat.

As she edged the Cat closer to the lip of the road, Rhiannon reduced the gap between her hands accordingly. "We're getting awfully close," she gulped, glancing down at the drop just inches away from her side of the Cat.

Emily rea.s.sessed her angle of approach to the s.p.a.ce between the stalled truck and the lip of the road. This was the best she could do without risking one of the tracks slipping off the edge. She wiped away a bead of sweat that had trickled into her left eye, then allowed her foot to caress the accelerator.

Gently, gently does it.

The Cat moved slowly forward, inching its way toward the gap.

The cab of the wrecked big rig loomed large on Emily's left side as she eased the Cat gradually past it, the left rearview mirror sc.r.a.ping noisily against the front edge of the truck's engine cowling. Emily ignored the screeching of metal against metal, focusing entirely on keeping the vehicle as far to the left as was possible.

The front two tracks of the Cat were clear of the cab now, safely on solid ground but with less than two feet of s.p.a.ce left between the front of the vehicle and the curving edge of the road. She brought the Cat to a dead stop and turned the wheel as far to the left as she could until she could see the tips of the left track poking out from beneath the gantry. She eased the vehicle forward, ignoring the gasp from Rhiannon as the kid surely saw how close the back of the Cat was to the edge. Pushing down on the accelerator, Emily glanced at the mirror on the right side of the cab; she could see the back right track was hanging over the precipice, spinning in midair above the drop-off.

And then the creatures. .h.i.t the almost stationary Cat like a tsunami, and Emily felt the vehicle slide farther sideways on the slushy ground. She couldn't see a thing now as the creatures hammered into the vehicle, fighting each other to get to the already open hole in the windshield.

Emily cursed and pushed harder on the accelerator, but it was useless. She couldn't see a thing, and, as more of the creatures joined those already jostling for position, she felt their added weight finally prove too much and gravity take hold.

Emily instinctively threw an arm out across Rhiannon's chest as she felt the front of the Cat begin to slowly tip skyward.

They balanced for a second on the lip of the cliff, and Emily thought that maybe, just maybe, the tracks would find some traction, but that thought quickly disappeared as she felt the Cat begin to slide over the edge. And then it was all too late.

It was over in a matter of seconds. But it felt like minutes.

Inside the Cat the cabin was dark, every inch of the exterior covered in the crawling horrors. That was probably a G.o.dsend. It meant Rhiannon wouldn't see the fall. But that didn't stop the girl from screaming as the ma.s.sive vehicle began to pick up speed, sliding backward down the cliff toward the valley floor below.

Emily felt the Cat begin to turn, the weight of the engine compartment dragging the front of the vehicle sideways, and for a moment she thought they were going to tip over and roll the remainder of the way. But the big vehicle remained upright as, now facing forward, they continued their slide.

One by one, the spider-aliens either leaped clear or were thrown from the Cat as it bounced and slid over the escarpment. Emily saw flailing forms of aliens bouncing past her, followed by an avalanche of snow and other debris.

The Cat hit something hard, maybe an outcrop of rock, and the right side lifted off the ground, dislodging more of the aliens into the air. The tracks came down again with a ringing of strained suspension springs that jarred the occupants and snapped Emily's teeth together painfully.

A rush of cold and snow entered through the windshield, filling the cabin with freezing air.

Emily had a clear view of the onrushing valley at the base of the escarpment as they hurtled toward it. Glancing over at Rhiannon, Emily could see the girl was pushed back into the support of her chair, her eyes pinched shut in terror.

"Hold on. It's almost over," she tried to say, but the words were lost in the rumble of the Cat's headlong fall.

Then came a bone-jarring shudder as the Cat thudded deep into a s...o...b..nk at the base of the cliff, sending a cascade of white powder high into the air. The Cat rocked three times as it settled back on its four creaking tracks.

All was silent.

"Are you okay?" Emily asked Rhiannon as she tried to unlatch the girl's safety harness.

Rhiannon opened her eyes and gave a weak smile, accompanied by two thumbs up.

Thor peeked his head back through the gap between Emily and Rhiannon, whining quietly. He was fine, apparently.

The Mossberg lay at Emily's feet. She picked it up and cradled it to her as she looked around the exterior of the cabin. The front of the Cat was buried almost up to the windshield in the s...o...b..nk that had finally brought them to a stop. But to the left and right of her, she could see an occasional broken limb sticking up from beneath the snow or the shattered carapace of an alien.

The only sound was their breathing. That meant the engine was dead. If it wouldn't start, then they would be as good as dead themselves out there. The temperature could drop to minus thirty in a heartbeat. There was no way they could survive and no hope of rescue.

Emily said a silent prayer to whatever G.o.ds might be looking over them and turned the ignition key. The engine fired up instantly, and Emily raised her eyes skyward in an equally silent thank-you.

She moved the gear stick into reverse and began to edge the Cat out of the wall of snow.

They had landed at the base of the ravine. On the right was a wall of rock that might just as well have been Everest; on the left was the final curve of the road. Beyond that was the open plain of snow that would lead them to their next destination.

Emily accelerated the Cat slowly, listening for any noises that might indicate a problem with the engine or a broken track. The only sound was the roar of the engine and the whistle of wind through the hole in the windshield.

"We'll have to do something about that," she said to Rhiannon, nodding toward the hole. "Or we're going to freeze to death in here." There was no way even the powerful heater could keep up with the freezing air that was rushing in.

They had lost the left mirror on the driver's side during the fall, and one of the supply boxes had broken open and spilled its contents over the back row of seats.

They left the ravine behind them, zagged left a few hundred feet across a field of white that seemed to stretch out to eternity, and then b.u.mped up onto the road.

Emily put another five miles behind them before she finally felt safe enough to stop the Cat and jury-rig a repair for the gaping hole. She emptied the remaining cans of food from the spilled cardboard box, then pulled it apart at the seams, taping the cardboard to the windshield with medical tape from the first aid kit.

"It ain't pretty, but it'll have to do," she said to Rhiannon, staring at the repair.

With nothing but clear road ahead of them now, the Cat picked up speed and roared down the road toward Coldfoot.