After the two Trisolaran Fleets had disappeared in the depths of space and the Trisolarans lost all contact with humankind, the extraterrestrial threats facing humanity took on an entirely new form. Fleet International, which had been formed to combat the Trisolaran invasion, lost its reason for existence and gradually diminished in relevance until it was finally dissolved. The Solar System Fleet that had belonged to Fleet International became the property of the Solar System Federation. This was the first time in human history where a unified world government controlled the majority of humanity's armed forces. Since it was no longer necessary to maintain a large space force, the fleet's size was drastically reduced. After the commencement of the Bunker Project, most of the then-extant hundred-plus stellar-class warships were converted for civilian use. After they were disarmed and their ecological cycling systems removed, they became interplanetary industrial transports for the Bunker Project. Only about thirty stellar-class warships remained in service. Over the last sixty-plus years, no new warships had been built because large warships were extremely expensive. It took the same amount of investment to build two or three stellar-class warships as it did to build a large space city. Moreover, there was no need for new warships. Most of the Federation Fleet's efforts were devoted to building the advance warning system.

The stellar-class ships were immense, but next to the space city they appeared as tiny skiffs around a giant ocean liner. The Federation Fleet had sent the bulk of their ships to enforce this blockade of Halo City.

As they approached Halo City, Cheng Xin and Cao Bin's dinghy encountered the Federation Fleet's blockade line. More than twenty stellar-class warships surrounded Halo City, and the blockade had lasted two weeks already.

The man who drifted over after the two vessels docked was middle-aged and dressed in a suit. Even in weightlessness, he moved gracefully and calmly, not appearing ill at ease at all in the cramped space that was meant only for two.

The dinghy stopped advancing as it received the blockade order. A military patrol boat sailed toward it. It was very small, and from a distance Cheng Xin could only see the glow from its thrusters -- its hull could be seen only once it got closer. When the patrol boat docked with the dinghy, Cheng Xin had a chance to look at the uniformed men inside it. Their military uniforms were very different from those of the last era and seemed to hearken to the styling of an earlier age. The uniforms had fewer space-based characteristics and looked more like the uniforms of old Earth-based armies.

"Good day. I'm Blair, special envoy of the Federation president. I'm about to try, for the last time, to negotiate with Halo City's city government. I could have talked to you from my ship, but out of respect for Common Era customs, I decided to come here in person."

"The Federation Government has announced a total blockade of Halo City, and no one is permitted to enter or leave. However, we know that the passenger here is Dr. Cheng Xin." The envoy nodded at her. "We give you permission to pass and will assist your entrance into Halo City. We hope that you will use your influence to persuade the city government to cease their deranged, illegal resistance, and prevent the situation from deteriorating further. I am expressing the wishes of the Federation president."

Cheng Xin noticed that even the politicians of this age had changed. The assertive and outspoken mannerisms of the last era had been replaced by prudence, restraint, and politeness.

The special envoy waved his hand and opened up an information window. The Federation president appeared in the window. In the office behind him were the flags of the various cities of the Bunker World, none of which were familiar to Cheng Xin. Nation states had disappeared along with their flags. The president was an ordinary-looking man of Asian descent. His face looked tired, and after nodding a greeting at Cheng Xin, he said, "Envoy Blair is right. This is the will of the Federation Government. Mr. Wade said that the final decision rests with you, an assertion that we do not fully believe. But we wish you the best of success. I'm glad to see you still looking so young. Although, for this matter, perhaps you're too young."

After the president disappeared from the window, Blair said to Cheng Xin, "I know that you already have some understanding of the situation, but I'd still like to give you an overall explanation. I'll strive to be objective and fair."

After Thomas Wade took over the Halo Group, the company became a key contractor in the Bunker Project. Within eight years, it had grown tenfold and become one of the largest economic entities in the world. Wade himself was not an extraordinary entrepreneur; indeed, he was not even as skilled as 艾 AA at managing the company's operations. The company's growth was the result of the new management team he put in place. He personally did not participate in the running of the company and had little interest in it, but much of the profit generated by the company was taken by him and reinvested in the development of lightspeed spaceflight.

Cheng Xin noticed that both the envoy and the president spoke only to her, ignoring Cao Bin's presence, indicating by this omission the deep enmity they felt toward him. As a matter of fact, Cao Bin had already explained the situation to her in detail, and the envoy's account wasn't too different.

As soon as the Bunker Project began, the Halo Group constructed Halo City as a research center. The Sun-Jupiter L2 Lagrangian point was chosen as the ideal space to set up Halo City in order to eliminate the need for city thrusters and the consumption of resources for position maintenance. Halo City was the only space science city outside the jurisdiction of the Federation Government. While Halo City was being constructed, Wade also began the construction of the circumsolar particle accelerator, a project that was dubbed "The Great Wall of the Solar System" because it enclosed the Sun in a ring.

For half a century, the Halo Group devoted itself to basic research for lightspeed spaceflight. Ever since the Deterrence Era, large companies had often engaged in basic research. In the new economic system, basic research could generate enormous profits. Thus, the behavior of the Halo Group wasn't too unusual. The Halo Group's ultimate goal of constructing lightspeed spaceships was an open secret, but as long as it stuck to basic research, the Federation Government could not accuse it of violating the law. However, the government continued to be suspicious of the Halo Group, and investigated it multiple times. For half a century, the relationship between the company and the government was basically cordial. Since lightspeed ships and the Black Domain Plan called for much of the same basic research, the Halo Group and the World Academy of Sciences maintained a good collaborative working relationship. For instance, the Academy's Black Hole Project used the Halo Group's circumsolar particle accelerator to produce its black hole specimen.

However, six years ago, the Halo Group had suddenly announced its plan to develop curvature propulsion ships. Such open defiance caused an uproar in the international community. Thereafter, conflict between the Halo Group and the Federation Government never ceased. After multiple rounds of negotiations, the Halo Group promised that when the curvature propulsion drive was ready for trials, the testing site would be at least five hundred AU from the Sun so as to avoid exposing the location of Earth civilization with the trails. But the Federation Government felt that the very development of lightspeed ships was a gross violation of the laws and constitution of the Federation. The danger of lightspeed ships lay not only in the trails, but also in upsetting the new social stability in the Bunker World, a prospect that could not be tolerated. A resolution was passed to authorize the government takeover of Halo City and the circumsolar particle accelerator, and to put a complete stop to the Halo Group's theoretical research and technical development in curvature propulsion. Thereafter, the Halo Group's behavior would be subjected to close monitoring.

In response, the Halo Group declared independence from the Solar System Federation. Thus, the conflict between the Halo Group and the Federation escalated yet further.

The international community did not take the Halo Group's declaration of independence too seriously. As a matter of fact, after the commencement of the Bunker Era, conflicts between individual space cities and the Federation Government were not infrequent. For instance, two space cities in the distant city clusters near Uranus and Neptune, Africa II and Indian Ocean I, had declared independence in the past, but nothing had ultimately come of those efforts. Although the Federation Fleet was nowhere near the size it had been in the past, it was still an overwhelming force if applied against individual space cities. By law, space cities were not allowed to possess their own independent armed forces -- they could only have limited national guards who had no capacity for space warfare at all. The economy of the Bunker World was also highly integrated such that no individual space city could survive a blockade longer than two months.

"On this point, I can't understand Wade either," said Cao Bin. "He's a man with foresight, and mindful of the big picture, and he never takes a step without having thought through the consequences. So why declare independence? It seems idiotic to provide the Federation Government with an excuse to take over Halo City by force."

The envoy had already left, and the dinghy, now occupied only by Cheng Xin and Cao Bin, continued on course to Halo City. A ring-shaped structure appeared in space ahead, and Cao Bin ordered the dinghy to approach it and decelerate. The smooth metallic surface of the ring reflected the stars as long streaks and distorted the image of the dinghy, bringing to mind the Ring that Blue Space and Gravity had encountered in four-dimensional space. The dinghy stopped and hovered next to the ring. Cheng Xin estimated that the ring's diameter was about two hundred meters across, and the band about fifty meters thick.

"You're looking at the circumsolar particle accelerator," Cao Bin said, his tone awed.

"Oh, sorry; I wasn't clear. This is but one of the coils in the particle accelerator. There are thirty-two hundred coils like this, each about one point five million kilometers apart, forming a large circle around the Sun in the vicinity of Jupiter's orbit. Particles pass through the center of these coils, where they're accelerated by the force field generated by the coil toward the next coil, where they're accelerated again… A particle might travel around the Sun multiple times during the process."

When Cao Bin had spoken to Cheng Xin about the circumsolar particle accelerator in the past, she had always pictured it as a giant doughnut hanging in space. But in reality, to build a solid "Great Wall" around the Sun, even within the orbit of Mercury, would have been an impossible feat approaching the level of God's Engineering Project. Cheng Xin finally realized that while an enclosed tubular ring was necessary for terrestrial particle accelerators to maintain vacuum, it was not necessary in the vacuum of space. The particles being accelerated could simply fly through space, being accelerated by one coil after another. Cheng Xin couldn't help turning to look past the coil for the next one.

"It's… rather small."

"The next coil is one point five million kilometers away, four or five times the distance from the Earth to the moon. You can't see it," Cao Bin said. "This is a supercollider capable of accelerating a particle to the energy level of the big bang. Ships are not allowed anywhere near the orbit of the accelerator. A few years ago, a lost freighter drifted into the orbit by mistake and was hit by a beam of accelerated particles. The ultrahigh-energy particles struck the ship and produced high-energy secondary showers that vaporized the ship and its cargo of millions of tons of mineral ore in an instant."

Cao Bin also told Cheng Xin that the circumsolar particle accelerator's chief designer was Bi Yunfeng. Of the past sixty-plus years, he had spent thirty-five of them working on this project and hibernated for the rest. He had been awakened last year, but was much older than Cao Bin now.

"The old man's lucky, though. He had worked on a terrestrial accelerator back during the Common Era, and now, three centuries later, he got to build a circumsolar particle accelerator. I'd call that a successful career, wouldn't you? But he's a bit of an extremist, and a fanatic supporter of Halo City independence."

The dinghy entered the axis of the giant wheel, where Cheng Xin and Cao Bin had to enter the city through an eight-kilometer spoke. This was one of the least convenient aspects of a wheel plan. Cheng Xin was reminded of her experience more than sixty years ago at the terminal station of the space elevator, and she thought about the great hall that reminded her of an old train station. But the feeling here was different. Halo City was more than ten times larger than that terminal station, and the interior was rather spacious and didn't look run-down.

The dinghy left the coil and continued its voyage. Halo City was straight ahead. This space city was built along the rarely seen wheel plan. The structure provided strength but had little interior volume, lacking "world-sense." It was said that the inhabitants of Halo City did not need world-sense, because for them, the world was the entire universe.

While the public and the politicians opposed lightspeed ships, many scientists supported the effort. Halo City became a holy site for scientists who yearned for lightspeed spaceflight and attracted many excellent researchers. Even scientists working within the Federation scientific establishment often collaborated with Halo City -- openly or in secret. This caused Halo City to be on the cutting edge in many areas of basic research.

Since the simulated gravity in the ring pulled toward the outer rim, the city was built along that surface. A holographic image of blue sky with white clouds was projected onto the inner rim, which made up some for the lack of world-sense. A flock of twittering birds flitted overhead, and Cheng Xin noticed that they were not holograms, but real. Here, Cheng Xin felt a sense of comfort that she had not experienced in the other space cities. There were plenty of trees and lawns everywhere. None of the buildings was very tall. Those belonging to the Academy of Sciences were painted white, while those belonging to the Academy of Engineering were painted blue, but each building was unique. The delicate buildings were half-hidden by the green plants, and made her feel as though she were on a college campus.

Cheng Xin didn't see any motor vehicles in the city at first. Most residents got around on bicycles, many of which were parked on the side of the road for anyone to use. But a small convertible motor vehicle came to pick up Cheng Xin and Cao Bin.

On the escalator of the spoke, gravity gradually set in. By the time it reached 1G, they were in the city proper. The science city was made up of three parts: the Halo Academy of Sciences, the Halo Academy of Engineering, and the Control Center for the circumsolar particle accelerator. The city was in fact a ring-shaped tunnel thirty-some kilometers in length. Although it wasn't nearly as open or spacious as the large, hollow shells of other cities, one didn't feel claustrophobic, either.

A few statues were scattered on the lawn next to the ruin. Cheng Xin's attention was drawn to one of the statues: A gauntleted hand was picking wreaths woven with stars out of a pool with a sword, and flowing water dripped from the wreaths continuously. This sight triggered something deep in Cheng Xin's memory, but she couldn't recall where exactly she had seen it before. She gazed at the statue from the motorcar until it disappeared.

Cheng Xin saw an interesting sight on her drive. There was a ruin like an ancient Greek temple. On a stone platform stood a few broken Greek columns covered with climbing ivy. In the middle of the columns was a fountain shooting a column of limpid water merrily into the sunlight. A few casually dressed men and women were leaning against the columns or lying on the lawn next to the fountain, lazing about comfortably. They seemed not to care that the city was under siege by the Federation Fleet.

The car stopped in front of a blue building. It was a laboratory marked with a sign: "Academy of Engineering, Basic Technology 021." Cheng Xin saw Wade and Bi Yunfeng on the lawn in front of the laboratory.

Bi Yunfeng should be much younger than Wade, but he looked older. He was very excited to see Cheng Xin and seemed eager to show her something.

Wade had never entered hibernation since taking over the Halo Group, and was now 110 years old. He kept his hair and beard short, but both were now white as snow. He didn't use a cane, and his stride was steady, but his back was a bit bent, and one of his sleeves still hung empty. In the moment they locked gazes, Cheng Xin understood that time had not defeated this man. What was at his core had not been worn away by the passing years, but had only become more prominent -- like a rock revealed after the snow and ice had melted away.

Cheng Xin faced these two old men with mixed feelings. They had struggled for their ideals for more than sixty years and were now near the end of their lives' journeys. She, on the other hand, had gone through so many trials after awakening for the first time during the Deterrence Era -- but in reality, she had spent no more than four years out of hibernation. She was now 33, still a young woman in this era where average life expectancy was 150.

"Hello, little girl," Wade said. "I'm now three times your age." His smile still couldn't make Cheng Xin warm, but it no longer felt as cold as ice water.

The machine's complex structure reminded Cheng Xin of a tokamak from the Common Era, but miniaturized. The bulk of the machine consisted of a sphere bisected horizontally by a flat black metallic plane that extended several meters over the edge of the sphere. The plane, holding up the sphere at about waist-height, also served as a lab bench with sturdy legs. The surface of the bench was mostly empty save for a few tools and manipulators attached to telescoping arms.

Cheng Xin greeted the two, and then no one wasted time by saying more. Wade led Cheng Xin into the laboratory with Bi Yunfeng and Cao Bin following. They entered a spacious, windowless hall. The familiar acrid odor of static told Cheng Xin they were in a sophon-free room. After more than sixty years, people still could not be sure that the sophons had left the Solar System, and maybe they'd never be sure. The hall must have been filled with instruments and equipment not long ago, but now all the lab equipment was scattered in a chaotic pile next to the walls, as though it had been moved away in a hurry to clear out the center. In the middle of the hall was a single machine. The surrounding chaos and the emptiness in the center displayed an irrepressible excitement, as though a team of treasure hunters had suddenly found a priceless artifact, tossed their tools to the side, and carefully moved their prize to the center of the open space.

The hemisphere above the bench, in contrast, was made of transparent glass. The two hemispheres together formed a whole divided by the metal plane, contrasting simple transparency with complex opacity.

Looking down through the glass dome, Cheng Xin could see a small rectangular metallic platform whose sides measured only a few centimeters, about the size of a pack of cigarettes, and whose surface was smooth and reflective like a mirror. The platform under the glass dome was like a tiny, delicate stage; and the complicated mechanism below the plane the orchestra that would accompany the performance, though it was unimaginable what that performance would be.

The metal hemisphere below the bench was studded with tubes of various thicknesses, all aimed at the invisible center of the sphere, causing the machine to look like a naval mine studded with Hertz horns. Apparently, the arrangement was designed to concentrate some kind of energy at the center.

"Let's allow a physical part of you to experience this grand moment," Wade said. Bi Yunfeng lifted the glass dome as Wade walked over to Cheng Xin and held up a pair of scissors. Cheng Xin tensed, but did not shy away. Carefully, assisted by a tool on the platform, Wade lifted a strand of her hair and cut off a small section at the end. He held the hair clipping with the tool, examined it, and concluded it was still too long. He cut the clipping in half so that the remaining piece was only about two or three millimeters long, almost invisible. Wade walked over to the side of the opened glass dome and carefully placed the hair on the smooth metal platform. Although Wade was over a hundred years of age and had only one hand, his movements were precise and steady, showing no tremors.

"Come, watch carefully," Wade said.

She saw that her hair had moved to the other side of the red line, but she hadn't seen it move.

Cheng Xin leaned down to look through the glass dome. She could see her hair resting against the smooth stage. There was a red line down the middle of the stage, and the hair was on one side of it.

Wade nodded at Bi Yunfeng, who opened a control window in the air and activated the machine. Cheng Xin looked down and saw that a few tubes connected to the machine began to glow red, reminding her of the glimpse she had caught of the inside of the Trisolaran spaceship. She heard a rumbling but didn't feel any heat. She returned her gaze to the small platform and felt some invisible disturbance spread out from the platform, brushing across her face like a light breeze. She couldn't be sure it wasn't just an illusion.

After another series of rumblings, the machine stopped.

"You spent half a century to move a three-millimeter section of hair two centimeters," said Cheng Xin.

"What did you see?" Wade asked.

"If we used the same technique to continue to accelerate the hair, it would be moving at lightspeed in about ten meters," Bi Yunfeng said. "Of course we can't achieve this now, and we dare not try it here. If we did, this bit of hair, moving at lightspeed, would destroy Halo City."

"It was curvature propulsion," Wade said.

"In fifty years, we should be able to construct curvature propulsion spaceships capable of lightspeed flight. This will require massive amounts of technical testing and development work. We have to lay our cards on the table now so that the government can back off and give us the environment necessary to carry out these tasks."

Cheng Xin pondered the strand of hair that had been moved two centimeters by curving space. "You are saying that you've invented gunpowder and managed to make a firecracker, but the ultimate goal is to make a space rocket. A thousand years may separate those two achievements."

"Your analogy is flawed," Bi Yunfeng said. "We have invented the equation relating energy to mass, and we've discovered the principle of radioactivity. The ultimate goal is to make the atom bomb. Only a few decades divide those two achievements."

To see these men in this age was akin to seeing a group of men armed with bows and swords during the Common Era. This was not to say that the fighters did not appear visually intimidating. Cheng Xin felt the presence of the past not only because of their ancient weapons, but also their appearance. They displayed a trained esprit de corps: they were uniform not only in dress and equipment, but also in their spirit. The men appeared tough and strong, with muscles bulging beneath their thin space suits. The gazes and expressions on their bold, angular faces were very similar: an indifferent, metallic grimness that viewed life as cheap as grass.

"But your current approach will make you lose everything."

"Everything depends on your decision," Wade said. "You must think that we're helpless against the power of that fleet out there. Not so." He gestured at the door. "Come in."

A group of forty or fifty armed men filed in and soon filled the hall. They were all young men dressed in black space camouflage, and their presence seemed to make the hall dimmer. They wore military-issue lightweight space suits that seemed no different from ordinary military uniforms, but they could enter space as soon as they put on helmets and life-support backpacks. Cheng Xin was astonished, however, to see the weapons they carried: rifles, from the Common Era. Perhaps they were newly made, but the design was ancient and entirely mechanical, with manual bolts and triggers. The ammunition they carried confirmed this: Everyone wore two crossed bandoliers filled with glistening yellow cartridges.

"This is our city self-defense force." Wade waved at the assembled men. "They are all we have to protect Halo City and the ideal of the lightspeed ship. You can see almost all of them here -- there are a few more outside, but the total is no more than a hundred. As for their equipment --" Wade took a rifle from one of the soldiers and pulled the bolt. "You can trust your eyes: ancient weapons constructed of modern materials. The bullets do not rely on gunpowder as the propellant and have much better range and precision compared to genuine ancient weapons. In space, these rifles can hit a ship from two thousand kilometers away, but fundamentally, they're primitive weapons. You must think this ridiculous, and I would, too, except for one thing." He returned the rifle to the soldier and pulled one of the cartridges from his bandolier. "As I said, the cartridges are basically of ancient design, but the bullets are new. So new, in fact, that they might as well come from the future. The bullet is a superconducting container and the interior is a pure vacuum. A magnetic field suspends a small ball in the middle to prevent it from contacting the bullet's body. The ball is made of antimatter."

The primitive-seeming cartridge held in Wade's hand now caused Cheng Xin to suffer chills. She now worried about the reliability of the containment magnetic field within that superconducting bullet: a single malfunction would be enough to cause the complete destruction of Halo City in a brilliant flash. She looked at the golden bandoliers hanging over the chests of every soldier: These were the chains of the god of Death. A single bandolier possessed enough power to destroy the entire Bunker World.

Bi Yunfeng's voice was filled with pride. "The circumsolar particle accelerator was not only used for basic research experiments, but also to produce antimatter. In the last four years, we've used it to make antimatter practically the entire time. We now possess fifteen thousand bullets of this design."

Wade continued, "We don't even have to go into space to attack. We just have to wait until the fleet approaches the city. We can shoot dozens or even hundreds of bullets at each of the twenty or so ships -- a single hit is enough to destroy it. Although the tactic is primitive, it's effective and flexible. A single soldier with a gun is a fighting unit capable of threatening an entire warship. Also, we have agents in other space cities with handguns." He returned the cartridge to the soldier's bandolier. "We don't want war. During the final negotiations, we'll show our weapons to the Federation envoy and explain our tactics. We hope the Federation Government will weigh the costs of war and abandon their threat against Halo City. We're not asking for much, only to build a research center several hundred AU from the Sun devoted to curvature propulsion testing."

Also, we have agents in other space cities with handguns.

"No," Wade answered calmly. "But neither can they. We can only try."

As soon as Cheng Xin saw the antimatter bullet in Wade's hand, she knew what she must do. She wasn't too worried about the Federation Fleet -- she believed that they'd come up with ways to deal with this tactic. Her mind was focused on only one thing:

"But if we go to war, can you guarantee victory?" Cao Bin asked. He had not spoken so far. Unlike Bi Yunfeng, he apparently was not in favor of war.

If war were to erupt, any of the guerrilla fighters hidden in the other space cities could casually shoot one of the antimatter bullets at the ground and the explosion of matter-antimatter annihilation would instantaneously tear apart the thin shell of the city and incinerate everything within. Next, the spinning space city would break into fragments and millions would die.

Space cities were as fragile as eggs.

Wade had not explicitly said that he would attack the space cities, but he also hadn't said he wouldn't. She again saw Wade aiming a gun at her 133 years ago -- an image which had been branded into her heart. She didn't know how cold a man would have to be to make such a decision, but the core of this man was the utter madness and coldness brought about by extreme rationality. She seemed to see again the young Wade from three centuries ago, screaming like a crazy beast: "Advance, advance without regard for consequences!"

As if confirming Cheng Xin's fear, a soldier spoke to her. "Dr. Cheng, please be assured that we will fight to the end."

Another soldier spoke up. "We are not fighting for you, for Mr. Wade, or this city." He pointed upwards, and fire seemed to light up his eyes. "Do you know what they're trying to take away from here? Not the city or lightspeed ships, but the entire universe outside the Solar System! There are billions and billions of new worlds out there, but they won't let us go; they want to lock us and our descendants in this prison, a prison fifty astronomical units in radius called the Solar System. We are fighting for freedom, for a chance to live as free men in the universe. Our cause is the same as every ancient struggle for freedom. We will fight to the very last. I speak for everyone in the self-defense force."

Even if Wade did not want to attack the space cities, what if others on his force did?

The other soldiers nodded at Cheng Xin, their eyes grim and cold.

In the years to come, Cheng Xin would recall the soldier's words countless times. But at this moment, they did not move her. She felt the world going dark, and she was mired in terror. She felt as though she was again standing in front of the UN headquarters, holding that baby from more than 130 years ago. She felt the baby in her arms was facing a flock of hungry wolves, and she had to protect the child at all costs.

Wade nodded. "Of course. Why else would I ask you to come here?"

"Then stop all preparation for war and cease all resistance. Turn over all antimatter bullets to the Federation Government. Order those agents you've sent to the other cities to do the same immediately!"

However, things did not develop as she expected. The gazes of the soldiers moved away from her one by one, turning to Wade. The suffocating pressure seemed to let up gradually, but she still had trouble breathing. Wade continued to look at the curvature propulsion platform under the glass dome holding up Cheng Xin's hair as though gazing at a sacred altar. Cheng Xin could imagine that Wade had once gathered his warriors around this altar to prophesy war.

"Will you keep your promise?" she asked Wade.

The soldiers gazed at Cheng Xin, as if trying to burn her to a crisp with their eyes. The power differential between the two sides was overwhelming. She was faced with a cold machine of war. Every man carried more than a hundred hydrogen bombs, and, led by a strong, mad leader, they formed a powerful black wheel capable of crushing all resistance. She was nothing more than a blade of grass in front of this giant wheel, not able to even slow down its progress. But she had to do what she could.

"There's no need." Cheng Xin's voice was like iron. "I have made my final decision. Cease all resistance, and turn over all antimatter in Halo City."

"Why don't you think about it some more?" Wade said.

"I choose human nature," Cheng Xin said, looking around at everyone. "I believe you all will, as well."

Wade lifted his head and looked at Cheng Xin with rarely seen helplessness and pleading. He spoke slowly. "If we lose our human nature, we lose much, but if we lose our bestial nature, we lose everything."

Bi Yunfeng was about to speak, but Wade stopped him. His eyes dimmed. Something had gone out in them, extinguished forever. The weight of years abruptly crushed him, and he appeared exhausted. He supported himself on the metal platform with his one hand and slowly sat down on a chair someone else brought over. Then he lifted his hand and pointed to the platform in front of him, keeping his eyes down. "Disarm. Leave all your ammunition here."

No one moved at first. But Cheng Xin felt something soften. That dark force was dissipating. The soldiers looked away from Wade and no longer focused on a single point. Finally, someone walked over and placed two bandoliers on the platform. Though his movements were gentle, the metallic sound made by the cartridges scraping against the platform caused Cheng Xin to shudder. The bandoliers lay still on the platform like two gold-colored snakes. A second man walked over and deposited his bandoliers, then more. The platform was soon covered by a golden pile. After all the cartridges had been collected, the metallic noises stopped, and everything became quiet again.

"Order all of our agents in the Bunker World to disarm and surrender to the Federation Government," Wade said. "The Halo City government will collaborate with the fleet to turn over the city. Do not take any drastic action."

"All right," someone answered. Deprived of their bandoliers, these men dressed in black space suits made the place even dimmer.

Wade gestured for the self-defense force to leave. They departed noiselessly, and the hall brightened as though a dark cloud had dissipated. Wade struggled to stand, walked around the pile of antimatter cartridges, and slowly opened the glass dome. He blew at the curvature propulsion platform and Cheng Xin's hair disappeared. He closed the dome, turned to Cheng Xin, and smiled. "You see, I've kept my promise, little girl."

After the Halo City Incident, the Federation Government did not immediately disclose the existence of antimatter weapons. The international community thought the event concluded as they had expected, and there wasn't much reaction. As the creator of the circumsolar particle accelerator, the Halo Group enjoyed great prestige internationally, and public opinion was mostly forgiving of them, suggesting that there was no reason to pursue anyone legally, and Halo City should be allowed to self-govern again as soon as possible. As long as the Halo Group promised to never again engage in any research and development of curvature propulsion and submitted to Federation monitoring, it should be allowed to go on with its business.

In the subsequent trial in Federation court, Thomas Wade was convicted of crimes against humanity, war crimes, and violations of the laws prohibiting research into curvature propulsion. The sentence was death.

Cheng Xin went to a detention center located near the Supreme Federation Court in Earth I, the Solar System Federation's capital, to see Wade one last time. They looked at each other through a transparent barrier and said nothing.

But one week later, Federation Fleet Command revealed to the world the captured antimatter bullets. The pile of golden Death stunned everyone.

The Halo Group was declared an illegal organization, and the Federation Government confiscated all its property and took over the circumsolar particle accelerator. The Federation Fleet declared a long-term occupation of Halo City, and the Academies of Science and Engineering were dissolved. More than three hundred people, including Wade, the other leaders of the Halo Group, and the city self-defense force, were arrested.

Cheng Xin saw that this old man, 110 years old, was as placid as the puddle at the bottom of a well that was about to dry out. There would be no more ripples.

Cheng Xin passed the box of cigars she had bought in Pacific I through an opening in the barrier. Wade opened the box, took out three of the ten cigars, and pushed the box back through the opening.

"I won't be able to use the rest," he said.

"Tell me more about yourself. Your work, your life. I want to tell those who would come later about you," Cheng Xin said.

"Do you have anything to say to me?" Cheng Xin asked. She was surprised that she wanted to hear his answer.

"Thank you for the cigars."

Wade shook his head. "I am but one of the countless who have died and will die. What is there to tell?"

Cheng Xin knew that what divided them wasn't just this transparent barrier, but also the deepest chasm in this world, a chasm that could never be bridged.

They sat in silence, neither looking at the other. Time turned into a stagnant pool that drowned them. Then, the tremors of the space city adjusting its position returned Cheng Xin to reality. She stood up slowly and softly said good-bye.

It took a long while before Cheng Xin understood that this was what Wade wanted to say to her. His last words. All his words.

Once she was outside the detention center, Cheng Xin picked out one of the cigars and borrowed a light from one of the guards. She took her first puff of a cigar in her life. Oddly, she didn't cough. She watched the white smoke rise in the sunlight of the capital, watched it dissipate in her tear-filled vision like the three centuries she and Wade had lived through.

Three days later, a powerful laser vaporized Thomas Wade in one-ten-thousandth of a second.

Cheng Xin returned to Asia I's hibernation center and awakened 艾 AA. They returned to the Earth.

They rode Halo back. After the Halo Group had been dissolved and its property confiscated, the Federation Government returned a small portion of the company's vast wealth to Cheng Xin. The amount was about equal to the value of the Halo Group at the time Wade took over. It was still a large sum, though minuscule when compared to the total wealth of the vanished company. Halo was part of the property returned to Cheng Xin -- though this was the third ship to bear that name. It was a small stellar yacht capable of seating up to three. The shipboard ecological cycling system was comfortable and refined, like a lovely small garden.

They returned to Australia. Only Canberra remained inhabited, and a tiny town government there called itself the Australian Federal Government. The Parliament House where Sophon had proclaimed the plan for the extermination of the human race was still there, but thick layers of vegetation sealed its doors, and vines climbed up the eighty-meter-tall flagpole. They found Fraisse's record in the government archives. He had lived until he was 150, but finally, time had defeated him. He had died more than ten years ago.

The longer they stayed on the Earth, the more all of civilization's history seemed a dream.

Cheng Xin and AA wandered over the barely inhabited continents of the Earth. They swept over endless forests, rode on trotting horses across grasslands, lingered over empty beaches. Most cities had become covered by forests and vines, leaving only small patches of civilization for the remaining residents. The total human population on the Earth was about what it was near the end of the Neolithic Age.

They went to Mosken Island. The lighthouse built by Jason was still there, but it was no longer lit. The region was completely uninhabited. They heard again the rumbling of the Moskstraumen, but all they could see was the empty sea in the light of the setting Sun.

Cheng Xin and AA rode Halo back to the Jovian city cluster and once again entered hibernation in Asia I. The contracted-for time was two hundred years, but they included a provision in the contract stating they should be awakened if a dark forest strike occurred before then.

Cheng Xin also wanted to go to that time, but not for a life of serenity. She had stopped a catastrophic war and she was becoming the target of the worship of millions. She could no longer live in this era. She wanted to see Earth civilization survive the dark forest strike and prosper after -- it was the only hope that could comfort her heart. She imagined life in that post-strike nebula. There, she would find true tranquility, maybe even happiness. That would be the last harbor of her life's voyage.

Their future was equally empty.

AA said, "Why don't we go to the world after the strike, the world after the Sun is gone? Only then will we find a life of serenity."

She was only thirty-three.

And then they slept. Dreamless.