Plague War

20

There was a second nano in Cam’s blood sample, a new machine shaped like a twisted X. Ruth had never seen it before, although she immediately thought of the dead mountaintop etched with thousands of crosses. The emotions in her now were the same — lonely confusion and despair. She leaned back from her tunneling scope and clenched her left ‚st in her brace, unable to get past the truth. It should be impossible, and yet the strange nanotech existed in his blood alongside the vaccine. His, but not hers. The nanotech was benign for the moment. Ruth expected it was waiting for some trigger.

Where had it come from?

“Let me out,” she said suddenly, turning to the microphone on her left. The clean booth was equipped with two open mikes, one to record her observations, the other to keep in contact with the outside because this booth was too small to enter or exit without help. For a laboratory, Grand Lake had built a reinforced steel box too small to hold all the equipment they’d gathered. A rack of electronics partially blocked the door and the bulk of an electron microscope crowded Ruth on her right, but the lab was sterile and well-lit and could draw more power than she needed, even to purge the box.

They knew the danger in some of what she was doing. The workbench was rigged with X-ray and ultraviolet projectors, which should at least slow an uncontrolled nanobot if not destroy it outright, and the air-conditioning could brie†y jump to eighty-mile-per-hour winds if necessary, vacuuming up any stray particles. It didn’t bear thinking about. The radiation would be bad enough for anyone inside the lab. Ruth expected the vacuum would also lift the scopes and machining tools in an upside down rain of metal, hard plastic, and lashing power cords — and of course if that didn’t eradicate any threat, they could just weld the box shut forever. It was like working inside a cof‚n.

“Let me out,” she said.

“What’s up?” McCown asked.

Ruth touched her white gloves to her mask. “I forgot my notes, I’m an idiot,” she said, ‚ghting to hold down the cold, bright edge of her claustrophobia.

Most days, that particular fear was only a scratching at the back of her mind. She had been enthralled to return to her work. It was unspeakably good to be in control again and Ruth had always excelled at ignoring everything beyond her microscopes, at least while she was making progress. Sometimes she lacked momentum. More than once her nerves leapt with a memory of planes or gun‚re. Another time, she saw ants that didn’t exist from the corner of her eye.

Ruth thought she had been very brave to step into this cramped box day after day, but now it was all that she could do to keep her heartbeat from affecting her voice.

“Please,” she said. “I know it’s a hassle.”

“Why don’t we have somebody get your notes for you,” McCown said. “We can read anything you want.”

“No.” The word came out too fast. “No,” she said carefully. “I should have worked through a couple ideas before I even bothered today. I was too tired after dinner.”

“Um. All right.” McCown sounded like he was frowning. “Give us a second.”

Ruth sagged against the workbench but caught an atmosphere hood with her elbow, a small glass sheath meant to snap onto the tunneling scope. The hood clanged and Ruth jerked and hit her head on a shelf. “Oh!”

McCown came back on the intercom. “Ruth?”

“Oh, shit,” she said, with just the right tone of casual disgust. “This place is like a shoebox.” Get me out, she thought. Get me out. Get me out.

“Five minutes, okay?” McCown said.

“Yes.” Ruth looked up at the harsh lights in the ceiling and then back and forth at the cluttered walls. Trapped. Then she leaned over the slim, elegant shape of the microscope again. It was her only escape.

McCown would probably be ten minutes, in fact. First he had to call for power to ramp up the air ‚lters in the prep room outside the lab. Then he’d run his clothes and especially his hair and hands against a vacuum hose before he stepped inside, locked the door, and repeated the process with another vacuum. Next he’d take his clothes bag down from the hooks on the wall and don his hairnet, mask, gloves, and baggy clean suit. It was only after this meticulous checklist that he would unlock Ruth’s door and help her stow her own suit.

She didn’t want him to see her panic. She needed to bury the feeling deep, but her best-learned coping mechanism left her in direct confrontation with the source of her fear.

Who made you? Ruth wondered, peering into the scope. The new nanotech was a ghost. It shouldn’t exist at all. Who could have made you, and where was Cam exposed? His blood sample contained only two of the new machines that Ruth had isolated so far, among thousands of the vaccine nano, but the ghost was very distinct. The ghost resembled a bent snippet of a helix, whereas the vaccine was a roughly stem-shaped lattice.

The ghost was beautiful in its way and Ruth brie†y forgot herself, caught in the mystery. She couldn’t help but admire the work it represented. Her quick estimate was that the ghost was built of less than one billion atomic mass units, which was damned small. The vaccine was barely under one billion AMU itself and as uncomplicated as they’d been able to make it. Could the ghost be a failed effort? Maybe the pair she’d found were only fragments of something larger. No. The two samples were identical. Even more interesting, the ghost had the same heat engine as the vaccine and the plague, which meant it had been built after the plague year by someone who was both capable of identifying the design work and reproducing it. The heat engine was a top-notch piece of engineering. Like Ruth and her colleagues, the ghost’s creator had seen no reason to reinvent the wheel. He’d put his energy elsewhere. This was obviously a functioning nano and it was biotech just like the vaccine, designed to operate inside warm-blooded creatures.

But what does it do? Ruth worried. The fear in her head felt like clots and lumps now, straining her ability to think.

What if the individual ghosts were meant to combine into a larger construct? Its helix shape could lend itself to a process like that. The trigger might be nothing more complicated than a heavy dose. Saturation. Cam appeared to have a low and ineffectual amount in his blood, but what if he absorbed more? Would it activate?

Whatever the ghost is for, it’s able to function above the barrier, she thought. So there’s no way to stop it. Then the latch in the door rattled and Ruth jumped and turned to shove herself against the heavy steel panel, nearly slamming it into Mc-Cown’s surprised face.

“Don’t touch a fucking thing,” she said.

* * * *

Ruth walked through the cold white sun in her Army jacket and thin pants, needing air, needing him. For the past three days she’d imprisoned herself for hours at a time. She’d barely seen Cam at all, which she regretted. They’d been so close to a relationship, but her schedule was practically nonstop — work, work, collapse, more work. Cam had moved out after the second morning, joining an effort to trap and inoculate rodents and birds in an attempt to reestablish some kind of ecology below the barrier.

The vaccine was widespread in Grand Lake. Cam had won that battle quickly, even though he’d appeared to be nothing except helpful and obedient. All of his coughing in the med tent. He’d outsmarted Shaug as easily as that, which was sort of funny. He always found a way, and she missed him now that their paths had separated.

Other people were moving apart, too. The exodus had been limited so far, but McCown said there were deserters in the military and Ruth could see for herself that the refugee camps were quieter than usual. Normally the two peaks across from her were busy with farming efforts. Today one of the terraced gardens was empty, and the work crews on another were de‚nitely understrength. Ruth understood. The temptation was too great. She was surprised that so many stayed. The new supplies were a help. Scavenging efforts had increased beneath the barrier, from organized convoys and helicopter runs to small handfuls of people who carried up as much as possible. Grand Lake had retained most of its population, at least for the short term. The habit was long ingrained. No one who’d survived would ever trust the world below ten thousand feet again, and the vaccine did not offer complete immunity.

At meals, she heard talk of relocating everyone to Boulder. Denver was much bigger, but it had taken fallout. There were also rumors that the Air Force would take a more aggressive stance and move a number of their people down into Grand Junction, a hundred and ‚fty miles to the west. Maybe it was even happening. Fighters and larger planes constantly roared away from the mountain and came back and left again and she couldn’t say if the amounts were the same. Some of them never returned because they were shot down, but maybe others were ‚nding new stations.

Snap decisions were a way of life up here and Ruth supposed she shouldn’t have been surprised to ‚nd herself propositioned by one of McCown’s assistants and then by the man who had the room next to hers in her shelter. They all felt like they had nothing to lose, and she was new and seemed unattached.

She stopped at the nearest mess hall. Snares and wire cages had been laid along the base of the long tent. A rat thrashed at the end of one line and Ruth stared at it with a weird mix of disgust and something else — her loneliness.

You got one, Cam, she thought.

There had never been much living up here, chipmunks, marmots, elk, and grouse and several other species of birds. Nearly all were extinct. The human population had tracked and killed every species beyond the point of sustainability. There might be a few grouse and chipmunks left in the region, but nobody had seen one for months. Occasionally birds still †itted overhead. And there were vermin. Rats were not indigenous to this elevation, but there must have been a few among the endless crates of FEMA and military supplies that were airlifted into the area during the ‚rst days of the plague.

The rats had †ourished in the crowded conditions and in the grime. Ruth supposed they should be glad. Had anyone, anywhere, managed to save other kinds of mammals? She wondered again at the bizarre world the next generation would inherit, assuming they didn’t ‚nish what the plague had started with a new contagion. Rats, birds, bugs, and reptiles made for a bleak and virulent environment, and yet it would be more stable than one without any warm-blooded creatures at all. Conservation efforts would become a way of life for centuries. Any dogs or horses or sheep that had survived would be priceless beyond measure. They must be out there in small numbers, hidden or lost on mountaintops around the world, which made it all the more important to preserve every single one.

The rat squirmed and clawed at the wire, snapping at its own leg. Ruth looked away from the ugly thing and saw two soldiers approaching. The man in front had unslung his ri†e, although he held the barrel toward the ground.

“This is a restricted area, Private,” he said. “You know that. Lunch isn’t for two hours.”

“Yes.” Ruth wore no insignia, so they thought she was a recruit looking for a way to steal or barter for extra food. She was probably lucky she was a woman, or they might have been rougher. McCown had given her a badge that showed her actual status, but Ruth saw no reason to take it from her pocket, which would create a record of where she’d gone.

She tried to smile and turned to leave. Then the soldier noticed the rat and glanced after her, his eyes hardening. He thinks I was planning to take it! she realized. That had been another bene‚t of the vermin. The rats had damaged crops and food stocks, but the rats had become food, too.

“I’m looking for Barrett’s group,” she said quickly. “Do you know if they’ve been through here today?”

The soldier relaxed slightly. Barrett was one of the leaders of the repopulation project, a civilian leader, although there were also troops assigned to the effort. “You’re late,” the soldier said, gesturing downhill to the west. “I saw some guys with cages at least an hour ago.”

“Thank you.” Ruth walked away. They were releasing the ‚rst rats into the old township in the hope that the little monsters would breed and continue down the face of the Continental Divide, clearing the area of insect swarms. It was a crazy idea. It was necessary. Rats were adaptable and cunning, which made them perfect to go up against the insects. Birds would be great, too, if Cam and his friends could ever catch and infect enough mating pairs.

* * * *

Ruth already knew she could make some improvements to the vaccine. She’d begun to work through new sensor models that would bump up its target-to-kill rate, but at Shaug’s insistence she’d set aside her theories to build and culture the snow†ake instead. There was no room for moral qualms. The world wouldn’t wait. The United States needed new weapons, because spy planes and satellites showed that the Russians already had close to ‚fty thousand troops on the ground, along with nearly half that many support personnel and refugees. The distinction was tough to make. During their endless struggle in the Middle East, the Russian population became a war machine, with everyone in combat or preparing for it.

U.S. and Canadian interceptors had begun to have more luck with hitting Russian transports before they reached the coast, but the invaders were †ying in from all directions now, down from the Arctic and the Bering Sea, up from the South Paci‚c— and they could land anywhere, not just in the mountains. Their planes hid and rose and hid again, deceiving North American radar and pursuit.

Two spearheads of Russian infantry had spread into Nevada while California burned. Uncontrolled blazes exploded through the diseased forests, both hindering the invasion and providing them with some cover. Ruth had seen the photos herself. Twice she’d sat down with generals and civilian agents to discuss the vaccine’s parameters and what kind of casualties the enemy could expect.

Ruth estimated the Russians’ short-term losses at 5 percent. Over a period of years, if the technology didn’t improve, there was no question that the internal war between the vaccine and the plague would lead to signi‚cant traumas and deaths, but in the meantime the invaders would merely be uncomfortable. Except for anyone who stayed in a hot spot, mostly they’d suffer only minor hemorrhaging and blister rash. Sometimes an unlucky individual might experience a bleeding eye or a stroke, perhaps a cardiac arrest, which could be costly if it was a pilot or a driver who was suddenly incapacitated.

The Russians were willing to pay that price. Their advance was staggered at times, but they’d claimed hundreds of miles, absorbing dead cities and airports, quickly motorizing their troops with abandoned vehicles and American armor — and they must have used the promise of the nanotech to win reinforcements.

The U.S.-Canadian net had detected huge †ights of Chinese aircraft rushing across the Paci‚c to strengthen the Russian foothold. Large naval †eets came behind. The enemy already held Hawaii. They’d attacked the tiny American outpost on Mt. Mauna Loa during the blackout after the electromagnetic pulse, risking an alert to the mainland. The islands were an ideal stepping-stone. The Chinese probably hadn’t thought twice about it. With the vaccine, they could win their ‚ght in the Himalayas even as they helped the Russians take control of industry-rich North America, its superior croplands, its military bases. The new allies could divide everything however they liked, unless Ruth stopped them. The snow†ake might be the only way for the U.S.-Canadian forces to regain the West, short of poisoning it with their own nuclear strikes.

She’d done it. She knew exactly how the snow†ake killed, but she’d rebuilt it with the same blind will of the rat in the snare. It hadn’t even felt like her decision. Millions of people needed the weapon’s power to survive. Millions more would die. The holocaust would always be her responsibility, but so were the lives she’d save. Her guilt colored everything she did. It affected her sleep. It kept her from approaching Cam even when she needed him more than ever.

The snow†ake was more of a chemical reaction than a true machine. It was originally one of several ANN developed by the scientists in Leadville, an anti-nano nano meant to destroy the plague. Composed of oxygen-heavy carbon molecules, the snow†ake was intended to disable its rival nanotech by drawing the plague into nonfunctional clusters. Each bunch would recombine around the original seed and shed more arti‚cially weighted grains, which would attract more plague, and so on. The process was termed “snow†aking” by its creator, LaSalle, but he had never been able to limit or regulate the effect.

The snow†ake tore apart all organic structures. A single wisp of it would liquefy all living things within hundreds of yards, people, insects, plants, even microbes and bacteria. Fortunately the chain reaction broke down in an instant. The snow†akes tended to glom onto each other as well as foreign mass and became encased in free carbon of their own making.

Cultivating it was extremely delicate work, for which Ruth donned one of Grand Lake’s few containment suits. One mistake could kill her. But the snow†ake did not attack rubber or glass.

She was forced to start from scratch. The data index included notes and information stolen from Leadville, but LaSalle’s ‚les had been unavailable. It didn’t matter. Her memory was nearly photographic and she’d helped LaSalle with early models of his baby. In fact, after the president’s council realized the true might of the snow†ake, Senator Kendricks had tried to recruit Ruth into LaSalle’s weapons group with the threat of losing a new arms race to the Chinese. At the same time, James Hollister had insisted that the Asians were years behind U.S. research.

Ruth didn’t know who to believe anymore. By itself, the new technology she’d called the ghost was proof enough that other scientists were still at work. The nanotech war had begun, almost unnoticed within the larger con†ict. She was afraid they’d already lost. The hundreds of sick people in the medical tents. The thousands of others who’d died undiagnosed in the long winter…How many of those casualties could be attributed to some as-yet-unknown effects of the ghost?

In three days she’d spent less than three hours trying to improve the vaccine. The rest had gone into preparing a genocide. It was a real chore to assemble the snow†ake by hand with inadequate gear and her ‚rst four efforts failed, too imbalanced to retain their purpose. Finally she had a single working snow†ake and locked it in a glass cap, carefully exposing it to a handful of weeds inside a larger glass. Breeding more was that easy. The weeds disintegrated and suddenly Ruth had trillions of the killing machines, although many of these new snow†akes were dead or half-strength. Ruth had to discard two hundred before she quit trying to sort through the mess, but during that time she found seven more snow†akes that were whole. Each of them went into a cap. Then she exposed those seven, too, after which she divided each of her eight teeming glasses into hundreds of smaller vials. Cluster bombs. Fifty vials to a case.

The snow†ake would also be effective in stopping the massive ‚res across the West, she’d realized. If they dispersed the nanotech along the front lines of a blaze, it would smother the inferno by reducing its fuel to dust. Maybe there were other peaceful uses.

If nothing else, she needed the snow†ake for testing. Eventually she hoped to design some way to protect people against it, like a weapon-speci‚c ANN, but the damned thing was just too basic. There was no proof that Ruth could imagine. Not yet. In time she might design a supernano that was capable of holding a person together against anything, even a bullet. It would be a form of immortality, an augmented immune system capable of sustaining good health.

Most important to Ruth, it would be the incredible technology to save Cam, using the blueprint of his DNA to restore his body and completely heal his wounds.

* * * *

She found him where the soldier had said, hiking up from the broad valley where the town once stood. Footpaths and crude jeep trails lined the slopes by the hundreds. Mud slides slumped across the barren earth. Here and there, stripped vehicles marred the land, cars and trucks that had bogged down or run out of gas during the ‚rst sprint for elevation. They were empty shells. Everything had been ripped away from them, seats, tires, hoods, doors, bumpers. The need for building material had been that severe. Far away, all that remained of the town were the right corners and straight lines of its foundations and streets, a small maze of squares set against the uneven shore of the lake. Several concrete structures remained, as did the fenced-off tarmacs of its three gas stations, but anything that was wood or brick or metal was gone.

Ruth felt nearly as forlorn. She worried at the choices she’d made. She could have had Cam, even for a moment, but she’d run to her work instead. It was the same choice she’d always made, even when one sweet hour together would have left her rested and better focused.

She didn’t want to die alone.

The sun had fallen away from noon in a hazy sky laced with contrails. Helicopters chattered somewhere in the north and Ruth wondered what they would do if the war suddenly fell on top of them. Run down, she thought. Run to him and keep running.

There were more than a dozen people with Cam, but Ruth recognized the way he carried himself even though his body was top-heavy with equipment. He’d slung a rack of wire cages over his shoulder. He wore a pack, too, and there were thick leather gloves tucked into his belt. Her chest lightened at the sight of him so clearly in his element…

Cam was laughing with a young woman. Ruth frowned. She had waited nearly an hour, holding her stone in her left hand, pressing its gritty surface into the soft, tender skin of her palm. She could have trudged down after him instead of staying with her thoughts, but she was sure he would have made the same decision. Be patient. Don’t risk infection.

Ruth tucked her rock into her pants pocket and walked to meet him, ruf†ing her ‚ngers through her bangs when the breeze tugged at her jacket and her curly hair. She needed a barber. When her hair got too long, it †uffed and made her look like Jimi Hendrix, which wasn’t particularly †attering. Still, the primping was unlike her and she knew it.

“Cam,” she called. He didn’t react. The wind was against her and he walked in the middle of the ragged group — ragged but in good health. Their voices were loud with the satisfaction of a job well-done, and yet Cam only directed his words at one of them. Allison Barrett.

“Next time just drop the cage,” he told her.

“That little fucker wouldn’t have made it anywhere near me and you know it,” Allison said, and Cam laughed again.

The girl was in her early twenties, Ruth thought, with a wide mouth and great teeth that she liked to show in a con‚dent animal smile. Bad skin. Most of it was sunburn but there were threads of plague scarring, too, especially on her left cheek. Her blond hair had been bleached almost white by the sun.

Ruth only knew her because Allison was one of the mayors elected in the refugee camps. After Ruth’s second meeting with Governor Shaug, Allison and three others had waylaid her escort in strident voices, demanding information. Shaug hadn’t dismissed them either, taking the time to introduce Ruth and to settle their questions. The refugees had clout if only because there were so many of them, and yet Ruth suspected the “mayors” had been a large part of Grand Lake’s ability to endure. For example, the trap-and-release project was absolutely genius. It showed the capacity to look ahead instead of allowing their many immediate problems to blind them to everything else.

Allison was clever and tough, exactly like Cam. Like the rats, Ruth thought, but that was uncharitable. She made herself smile as the work crew approached, carrying Allison and Cam along in the middle. Their heads were still turned toward each other. Allison noticed her ‚rst.

“Hi,” Ruth said.

Cam hesitated. His body language toward Allison was calm and open, but his eyes grew troubled. It was a complex exchange and Ruth missed none of it.

He said, “Ruth, what are you doing here?”

“I need a minute.”

“Okay.” He set down his cages and his gloves. That he didn’t question her at all made Ruth feel good. They could still rely on each other, no matter what else.

Ruth caught his arm and drew him aside, glancing at Allison to make certain the girl didn’t follow. Stupid. If she and Cam had touched each other — if they were having sex — Ruth would need to test Allison for the ghost, too, but her instinct was to protect Cam and that meant keeping the contagion a secret as long as possible.

She let go of his sleeve. Being close to him evoked more feelings than she was ready for and she was glad to move into the wind.

I’m jealous, she realized, too late.

Ruth had been using samples of his blood and her own because they were the original carriers of the vaccine. It was widespread now, but that was just good science, and a good excuse to see him.

“There’s a problem with your work,” Cam said, watching her. His intuition was straight on the mark and Ruth was suddenly afraid of what else he might see in her.

“Where have you been?” she asked, harried and intense.

“We took some rats into town,” he said. “There’s still a chance—”

“Where have you been, Cam?” Ruth clutched his wrist to make sure she had his attention, searching his brown eyes. He stared back at her, a little frightened now. Ruth said, “In the lab in Sacramento, did you go anywhere? Did you open anything?”

“What are you talking about?”

“There’s something else inside you, a new kind of nanotech. Maybe a weapon. There’s something else besides the vaccine and I don’t know what it is.”

“I — Oh my God.” Cam stepped back from her, staggering. Ruth quickly moved after him, but he brought his forearms up between them, looking at his hands as if he thought he could possibly see the subatomic machines.

“You know I’ll do everything I can,” Ruth said, sharing his fear. It was strange. She felt a very welcome intimacy in the moment. On some basic level, she had learned to associate Cam with tension and pain, and now they were bound together by those feelings again.

Hurting for him, she watched his face. She also was aware of his friends shifting behind her, and she was glad for their voices and the rustle of their boots. Standing apart from them only heightened her sense of rejoining Cam.

“What do you remember about Sacramento?” she asked.

“I don’t think I went anyplace that the rest of us didn’t go, too,” he said. Then, more ‚ercely, “I didn’t. I swear.”

Ruth matched his quiet tone. “We’ll ‚gure it out,” she said.

Allison intruded. Allison edged past Ruth, walking like a cat. The girl held her body low but kept her shoulders up, her hands ready to grab or punch. It was a posture that she must have learned in the camps, Ruth thought, light-footed and able.

“What’s going on?” Allison said. Her voice was as full of challenge as the way she held herself and Ruth met it without thinking.

“I’ll need blood samples from you, too,” Ruth said, trying to scare the girl.

Allison only grinned at her. “Is that why you’re here?” Allison asked. Then she took Cam’s hand in her own and stood with the shoulder of her tattered blue sweater against his Army jacket.

“There’s a new kind of nanotech,” Cam said, explaining to Allison.

The two women never looked away from each other. Ruth tried not to let her defeat show in her face — or her respect. Allison was plucky and bold. In fact, the girl reminded Ruth of herself at her best, but she just wasn’t that con‚dent anymore. Allison was willing to rush an opportunity. Ruth was not. Otherwise she wouldn’t have missed her chance before Cam and Allison met.

Watching him with the girl made it clear. Even with his rugged looks, there had been no shortage of attention for who he was and what he’d accomplished, and their acceptance of him was exactly what he’d missed.

And you deserve it, Ruth thought.

Still, she was crushed. Cam must have exhausted his patience with her during their long run, and yet this was the only time she’d known him to veer away from what he really wanted. In some way, Ruth supposed he was trying to punish her. She saw that now. His decision to pair up with Allison was self-destructive, complicating his relationship with the woman he really wanted. Ruth knew that he loved her. Finding someone else, simply taking the opportunity, was an attempt to reject Ruth before she had the chance to say no. But she loved him, too. Couldn’t he see that?

She didn’t doubt that Allison’s attraction to him was genuine, but she was suspicious of the girl’s reasons. Allison would always be looking to strengthen her faction here in Grand Lake, and Cam was both a celebrity and a veteran survivor. So the girl had tied herself to him.

“You better come with me,” Ruth said, looking away from Allison to include the others in the group. “All of you. I need blood samples before you go anywhere else.”

* * * *

She turned her back on Cam in a daze. She knew what she had to do. A discovery as criticial as the ghost could not be left for later, so Ruth went forty-eight hours with only a few catnaps and two big meals, hiding herself in the lab.

Was the ghost a Chinese construct? She knew that in Leadville, intelligence reports had put China’s research program at the top of the list after Leadville itself. The plague year had badly confused things, of course, and a nanotech lab could be small and easily hidden, but at the same time, the world had shrunk to a handful of island ranges. There were fewer places to watch. Their list of competitors was very short. China. Brazil. India. Canada. There was a displaced Japanese team on Mt. McKinley, Alaska, and a British group in the Alps. All except the Chinese had been considered friendly. Regardless, Ruth didn’t think any of them except the Chinese were capable of building the ghost, so it must be a threat.

She had been wrong in her initial assessment. The ghost was 15 percent smaller than the vaccine, but more advanced. It was a high-level construct and in its complexity Ruth was able to discern the tiniest changes. Generations. A few blood samples from McCown and his assistants seemed to indicate that it had spread through the local population in waves. An early model was followed by another. Possibly more. Cam had probably gotten it from Allison, and Ruth continued to fear that the ghost was only waiting to reach some critical mass before decimating Grand Lake.

Was it everywhere across the Continental Divide? Shaug allowed her to send radio queries to the labs in Canada, and the answer was no. So where had the technology come from?

The ghost was in Ruth, too. It appeared in her blood on their fourth day, just a half step behind Cam’s infection, which ‚t with her hypothesis. The count in Newcombe’s sample was also low. They hadn’t brought it to Grand Lake. Grand Lake had infected them.

After that, her tactics changed. Ruth insisted on blood samples and basic information from a thousand soldiers and refugees, beginning a crash program to backtrack the ghost’s origins. For two more days she dedicated computer time to the task along with most of McCown’s group and dozens of overworked medical staff. She was ‚ghting her own people. Shaug and the military leaders pressed her for new and better weapons. Ruth refused. It was the wrong priority.

Deborah Reece became a crucial ally and volunteered to oversee the blood work. Ruth let herself be interrupted to monitor the snow†ake production, but mostly she’d handed that effort off to McCown.

The land war was rapidly escalating to the brink. The Chinese naval †eet swarmed into San Diego and Los Angeles and dispersed tens of thousands of infantrymen, armored units, and aircraft, opening a new front against the United States. Meanwhile the Russians continued to push through Nevada — and the invaders were winning the battle for air supremacy. The Russian air force was full of relics and mismatched planes, and the Chinese had similar problems, but even at half strength they dominated the United States, especially as America continued to shuf†e working aircraft into key positions.

Each side tried to protect their planes and fuel supplies even as they sent ‚ghters slashing into each other’s territory. Each side rushed to claim airports and old U.S. bases, destroying some, protecting others, a game of chess with negotiations †aring and failing. The U.S.-Canadian forces threatened full-scale nuclear strikes on mainland China and the Russian motherland if the invaders did not immediately pull back to the coast, while the Chinese swore they’d respond in kind, plastering the Continental Divide at the ‚rst sign of an American missile launch.

It should have been insigni‚cant, but Ruth also had to confront Allison every morning as Cam and Allison helped to deliver the samples and geographical data from hundreds of refugees. Ruth couldn’t help believing that Allison and Cam were a good match, both of them scarred but still young and strong, savvy and dedicated.

In fact, Ruth went to Allison ‚rst after she’d made her decision.

* * * *

She caught her just after sunrise. Cam and Allison were inside a broad tent where they’d set up a dozen benches, a dry-erase board, and four desks to process the refugees who came in exchange for a granola bar or an extra piece of clothing. There was already a crowd forming outside.

Cam had his head together with an Army medic over a clipboard. Ruth walked past them. She felt ill with tension and lack of sleep and Allison grinned at her. It wasn’t a mean gesture. The girl knew she’d won, and Ruth thought she was only trying to be friendly. Possibly there was just the smallest hint of amusement or pity in the way she treated Ruth for being older, too old for Cam.

“Hello,” Allison said.

“We need to get out of here,” Ruth said bluntly. She was angry that anyone could seem so content, and took satisfaction in wiping away Allison’s big smile.

“Oh shit,” the girl said. “Cam told us it was probably a weapon—”

“No. No, I still don’t know.” Ruth shook her head at herself. She had no right to blame Allison. But she had her suspicions about who had designed the ghost. She recognized the work. Every machinist had his or her own style, exactly like painters, writers, and musicians. The ghost wasn’t Chinese. It was American. The new technology belonged to Gary LaSalle, and Ruth said, “I think it came from Leadville. I think Leadville cornered our friends before they made it into the Sierras and then they had the vaccine, too, which means they could have run spin-offs for at least a week and a half before the bombing.”

“I’m sorry,” Allison said. “Who had the vaccine?”

Ruth realized she wasn’t making sense. Cam would have understood, but Allison hadn’t been there. “I need your help,” she said.

“You bet.” Allison nodded, watching her face closely. The girl had ‚nally noticed Ruth’s exhaustion.

“There were two more people with us who made it out of Sacramento,” Ruth said. “A soldier and another scientist like me. They had the vaccine. Leadville caught them. That was about two weeks ago, and Leadville must have started running trials and new versions based on that technology.”

There were four different strains of the ghost. Ruth had solved that much of the riddle without coming any closer to knowing what the ghost was supposed to do. At the same time she’d also identi‚ed, very roughly, four infection points that had since blended as the remnants of Leadville’s armies split and surrendered and migrated away from ground zero. The leadership there had been secretly testing new models of the ghost on their own people. They’d dosed forward units to see what would happen — and yet the ghost was not a perfect vaccine, even though it should have been easy for them to improve the crude, hurried work that Ruth had done in Sacramento.

The teams in Leadville never would have left the vaccine exactly as it was, not bothering to improve it. Ruth knew that much. A better vaccine must exist. Leadville’s machining gear far exceeded anything that Grand Lake had been able to steal or buy. Leadville also had the expertise of ‚fty of the best minds in nanotech. A vaccine that offered full immunity against the plague would have been their ‚rst priority, but they must have kept it for themselves exactly as she’d feared. Then they’d begun to experiment with other nanotech.

What did the ghost do? Could she recover the improved vaccine somewhere? Ruth would never be able to match their work or recreate it on her own, not for years or decades, but there might be survivors from their inner circle or molecular debris that had been thrown clear of the blast and absorbed by the nearest refugees. She was certain she could ‚nd other traces of their handiwork, if only she looked.

“We have to get out of here,” Ruth said, “and I need you to help me convince Shaug to let me go. I need an escort. Cars. My equipment.”

“That won’t be easy. I can talk to the other mayors.”

“Thank you.”

Ruth needed to follow the muddled, invisible trail back into the south to see if she could recover LaSalle’s best work before it was lost forever. There wasn’t anyone else who could sort through and identify the nanotech.

“Do you think Cam…Will he come?” Ruth ducked her head from Allison’s gaze and spoke to the †oor. “He’s ‚nally safe here. And he has you and his other friends.”

Allison waited until Ruth looked up again, then shook her head and smiled once more. This time the smile was sad, and Ruth understood that Allison carried her own resentment. In fact, Allison would have been glad to see her go.

“Try to stop him,” Allison said.