Although she was an aerospace engineer from the Common Era, Cheng Xin had never been in space until this day, three centuries later. It no longer required special training to ride any space vehicles, but in consideration for her lack of experience, the technical support staff suggested that she ascend in the space elevator. Since the entirety of the ride was conducted at the same speed, there would be no hypergravity. And the gravity inside the elevator car now wasn't noticeably lower -- gravity would diminish gradually, until she achieved complete weightlessness at the terminal station in geosynchronous orbit. At this altitude, one would experience weightlessness only when orbiting the Earth, not when going up in a space elevator. Occasionally, Cheng Xin saw tiny dots sweep past in the distance -- probably from satellites coasting at first cosmic velocity.

Viewed through the portholes in the elevator, Cheng Xin's entire world consisted of an eighty-centimeter-thick guide rail. The guide rail extended endlessly both above and below her, shrinking into invisibility in each direction. She had been riding for an hour already and was more than a thousand kilometers above sea level, outside the atmosphere. The Earth below her was in the shadow of night, and the continents were mere hazy outlines with no substance. The space above her was inky blackness, and the terminal station, thirty thousand kilometers away, was invisible. One felt as though the guide rail pointed to a road from which there was no return.

The guide rail's surface was very smooth, and it was almost impossible to see motion. The elevator car seemed to be sitting still on the rail. In reality, her velocity was fifteen hundred kilometers per hour, equivalent to a supersonic jet. Reaching geosynchronous orbit would take about twenty hours, which made this a very slow journey in the context of space. Cheng Xin recalled a conversation during college where Tianming had pointed out that in principle, it was perfectly possible to achieve spaceflight at low speeds. As long as one maintained an ever-upward speed, one could go into space going as slow as a car or even walking. One could even walk up to the orbit of the moon in this manner, though it would be impossible to step onto the moon -- by then, the relative velocity of the moon with respect to the climber would be more than three thousand kilometers per hour, and if one were to attempt to remain at rest with respect to the moon, the result would once again be high-speed astronautics. Cheng Xin clearly recalled that he had said at the end that it would be an amazing sight to be in the vicinity of the moon's orbit and watch the gigantic satellite sweep overhead. She was now experiencing the low-speed spaceflight he had imagined.

The elevator car was shaped like a capsule, but divided into four decks. She was in the top deck, and those who accompanied her were in the lower three decks. No one came up to bother her. She was in the luxurious business-class cabin, like a room in a five-star hotel. There was a comfortable bed and a shower, but the suite was small, about the size of a college dorm room.

She was always thinking about her time in college these days, thinking about Tianming.

At this altitude, the Earth's umbral cone was narrower, and the Sun thus became visible. Everything outside was submerged in the powerful, bright light, and the portholes automatically adjusted to decrease their transparency. Cheng Xin lay on the sofa and watched the guide rail above her through the porthole overhead. The endless straight line seemed to descend directly from the Milky Way. She wanted to see signs of motion against the guide rail, or at least to imagine it. The sight was hypnotic, and eventually she fell asleep.

She heard someone call her name softly, a man's voice. She saw that she was in a college dorm sleeping in the bottom bunk of a bunk bed. But the room was otherwise empty. A streak of light moved across the wall, like streetlights inside a moving car. She looked outside the window and saw that, behind the familiar Chinese parasol tree, the Sun swept across the sky rapidly, rising and setting every few seconds. Even when the Sun was up, however, the sky behind it remained inky black, and the stars shone along with the Sun. The voice continued to call her name. She wanted to get up to look around, but found her body floating up from the bed. Books, cups, her notebook computer, and other objects floated around her…

Cheng Xin woke up with a start, and found herself truly floating in air, hovering a small distance above the sofa. She reached out to pull herself back onto the sofa, but inadvertently pushed herself away. She rose until she was next to the porthole in the ceiling, where she turned around weightlessly and pushed against the glass, successfully sending herself back to the sofa. Everything looked the same in the cabin, except that the weightlessness released some of the settled dust motes, and they sparkled in the sunlight.

"Dr. Cheng, I understand this is the first time you've been in space?" he asked.

She saw that an official from the PDC had come up from the cabin below. It was probably he who had been calling her name earlier. He stared at her, astonished.

After Cheng Xin nodded, he smiled and shook his head. "But you look like an old spacer."

Cheng Xin herself felt surprised as well. This first experience of weightlessness did not cause her discomfort or anxiety. She felt relaxed, and there was no dizziness or nausea. It was as if she naturally belonged here, belonged to space.

Cheng Xin looked up. She saw the guide rail again, but now she could tell they were moving by its surface -- a sign that they were slowing down. At the end of the rail, the geosynchronous terminal station was coming into view. It was formed of multiple concentric rings connected together by five radial spokes. The original terminal station was just a small part in the center. The concentric rings were later additions, with the outer rings being newer. The entire structure slowly rotated in place.

"We're almost there," the official said, pointing up.

Cheng Xin also saw other space buildings appear around her. The dense cluster of buildings in this region was the result of engineers taking advantage of proximity to the space elevator terminal station for transportation of construction materials. The buildings were of different shapes and appeared from the distance as a bunch of intricate toys -- only when one swept past at close range could their immensity be felt. Cheng Xin knew that one of these housed the headquarters of the Halo Group, her space construction company. AA was working in it right now, but she couldn't tell which building it was.

The elevator car passed through a massive frame. The dense struts in the frame made the sunlight flicker. By the time the car emerged from the other end of the frame, the terminal station took up most of the view, and the Milky Way twinkled only from the space between the concentric rings. The immense structure pressed down, and as the car entered the station, everything dimmed as though the car was entering a tunnel. A few minutes later, bright lights illuminated the outside: The car was in the terminal hall. The hall spun around the car, and for the first time Cheng Xin felt dizzy. But as the car detached from the guide rail, it was clamped by the platform. After a slight jolt, the car began to spin along with the station, and everything around her seemed to be still again.

Cheng Xin, accompanied by four others, emerged into the circular hall from the car. As their car was the only one at the platform, the hall seemed very empty. Cheng Xin felt a sense of familiarity right away: Although information windows floated everywhere, the main structure of the hall was built from metallic materials that were rare in this age, mainly stainless steel and lead alloys. She could see the marks left by the passage of years everywhere, and she felt herself situated in an old train station instead of in space. The elevator she had ridden was the first space elevator ever built, and this terminal station, completed in Year 15 of the Crisis Era, had been in continuous operation for more than two centuries, even through the Great Ravine. Cheng Xin noticed the guardrails crisscrossing the hall, installed to help people move around in weightlessness. The guardrails were mainly made of stainless steel, though some were made from copper. Observing their surfaces, bearing the marks of countless hands through more than two centuries of service, Cheng Xin was reminded of the deep ruts left in front of ancient city doors.

The rails were leftovers from an earlier age, since everyone now relied on individual tiny thrusters which could be worn on the belt or over the shoulders. They generated enough thrust to propel people around in weightlessness, controlled by a handheld remote. Cheng Xin's companions tried to give her a first lesson in space -- how to use the weightless thrusters. But Cheng Xin preferred to navigate around by grabbing on to the guardrails. As they arrived at the exit to the main hall, Cheng Xin paused to admire a few propaganda posters on the wall. These were ancient, and most of them dealt with the construction of the Solar System defense system. In one of the posters, a soldier's figure filled most of the image. He was dressed in a uniform unfamiliar to Cheng Xin, and his fiery eyes stared at the viewer. Below him was a line of large text: The Earth needs you! Next to it was an even larger poster in which people of all races and nationalities stood, arms linked, to form a dense wall. Behind them, the blue flag of the UN took up most of the picture. The text on the poster read: Let us build a new Great Wall for the Solar System with our flesh! Although Cheng Xin was interested in the posters, they didn't feel familiar. They seemed to harken back to an older style, reminding people of an age before she had even been born.

That had been a brief, despotic age, when the whole world had been militarized before everything, from faith to life, collapsed… But why had these posters been kept until now? To remember, or to forget?

"These were from the beginning of the Great Ravine," one of the PDC officials traveling with her said.

Cheng Xin and the others exited the main hall into a long corridor, whose cross section was also circular. The corridor extended ahead of her for some distance, and she couldn't see to the end. She knew that this was one of the five radial spokes of the station. At first, they moved in total weightlessness, but soon, "gravity" appeared, in the form of centrifugal force. At first, the force was very weak, but it was enough to induce a sense of up and down: the corridor suddenly turned into a deep well, and instead of floating, they were falling. Cheng Xin felt dizzy, but many guardrails protruded from the wall of the "well." If she felt she was falling too fast, she could decelerate by grabbing on to one of the rails.

They passed the intersection between the spoke and the first ring. Cheng Xin looked to the right and left, and saw that the ground rose up on both sides, as though she were at the bottom of a valley. Over the entrances to the ring on both sides were red-glowing signs: First Ring, Gravity 0.15G. The wall of the curved corridor of the ring was punctuated by multiple doors, which opened and closed from time to time. Cheng Xin saw many pedestrians. They stood on the floor of the ring due to the microgravity, but they still moved by leaping ahead with the aid of the weightless thrusters.

After passing through the first ring, the weight increased further, and free-falling was no longer safe. Escalators appeared on the wall of the "well," one going up and one going down. Cheng Xin observed the passengers riding up and saw that they were dressed casually, indistinguishable from Earth dwellers. The wall of the well had many information windows of different sizes, and more than a few of them were broadcasting the image of Cheng Xin stepping onto the space elevator more than twenty hours ago. But at the moment, Cheng Xin's four escorts surrounded her, and she was also wearing her wide-framed sunglasses. No one recognized her.

As they descended, they passed through seven more concentric rings. As the diameter of each successive ring grew, the curvature of the corridors to the sides became less noticeable. Cheng Xin felt as though she was passing through strata of history. Each ring used different construction material from the rings before it, and looked newer. Each ring's method of construction and decorative style formed a time capsule of an age: the repressive militaristic uniformity of the Great Ravine; the optimism and romanticism of the latter half of the Crisis Era; the hedonistic freedom and indolence of the Deterrence Era. Before the fourth ring, the cabins in the rings were integrated into the structure of the rings, but starting with the fifth ring, the rings only provided construction spaces, and the buildings in the rings were planned and constructed later as additional fixtures, showing a rich variety of styles. As Cheng Xin descended through the rings, signs of this being a space station gradually faded, and the environment resembled daily life on the surface more. By the time they reached the eighth ring, the outermost ring of the station, the construction style and scenery were indistinguishable from a small city on the surface. The corridor looked like a bustling pedestrian promenade. Add to that the standard gravity of 1G, and Cheng Xin could almost forget that she was in space, thirty-four thousand kilometers above the Earth.

They passed by the rows of spacecraft until they arrived at a small open space at the end of the port. There, a small spaceship -- a dinghy, really -- sat by itself. Next to it stood a group of people who had apparently been waiting for her. The Milky Way slowly swept by the open side of the port, and its light cast long shadows from the dinghy and those standing next to it, turning the open space into a giant clock, over which the roving shadows acted as hands.

But the city scene soon disappeared, as a small motor vehicle brought them to a place where they could see space again. The entrance to the flat hall was marked with "Port A225," and a few dozen small spacecraft of various designs parked on the smooth, plazalike floor. One side of the hall was completely open to space and the stars spinning around the station. Not too far away from them, a bright light started to glow, illuminating the whole port. Gradually, the light turned from orange to pure blue, and the spaceship that had turned on its engines lifted off the floor, accelerated, and shot into space from the open side of the port. Cheng Xin was witnessing a technological miracle that had become commonplace for others, but she couldn't figure out how it was possible to maintain atmosphere and pressure in space without the area being completely enclosed.

The group next to the dinghy consisted of the special team convened by the PDC and the fleet for this encounter. Cheng Xin knew most of the members -- they had attended the Swordholder handover ceremony seven years ago. The two team heads were the rotating chair of the PDC and the chief of staff for the fleet. The rotating chair was new, but the fleet chief was the same person as before. These seven years, the longest in the history of the human race had left indelible marks on their faces. No one said anything as they silently shook hands and silently remembered.

Cheng Xin examined the dinghy before her. Short-range spacecraft now came in a variety of shapes, but the streamlined profile popular in the imagination of past generations was absent. This dinghy had the most common shape: a sphere. It was so regular that Cheng Xin couldn't even tell where the thruster was. The dinghy was about the size of an old medium-sized bus. It had only a serial number and no name. This common vehicle was going to carry her to the meeting with Yun Tianming.

That much Cheng Xin already knew, but now she was told something much more important.

Why conduct the meeting in space? In an age where neutrino communication was possible, being in space wasn't much more isolated than being on the surface of the Earth. Sophon had explained the request as symbolic: The meeting should occur in an isolated environment to show that it was independent of both worlds. The Lagrangian point was chosen to allow Cheng Xin's position to be relatively stable. Also, it was the long-held custom among Trisolarans to conduct meetings at points of balance between celestial bodies.

The meeting was to take place at the point where the Earth's and the Sun's gravities balanced each other: a Lagrangian point about 1.5 million kilometers away. The sophons would facilitate the meeting with their real-time link with the First Trisolaran Fleet. There would be both voice and video.

The fleet chief brought Cheng Xin into the dinghy. There wasn't much room inside, just enough for four people. As soon as the two of them sat down, half of the spherical hull -- the part facing them -- became transparent, so that they seemed to be sitting inside the helmet of a gigantic space suit. This type of dinghy was chosen in part for its open field of view.

The fleet chief paused, and only after a long while, as though he had to prepare himself, did he explain the red light. "If they think you're being given information you may not receive, the red light will be lit."

"These three lights are controlled by Sophon. Your meeting will be monitored throughout by the Trisolarans. As long as they believe the contents of your conversation are acceptable, the green light will stay on. If they wish to warn you about topics verging on the unacceptable, the yellow light will be lit."

Modern spacecraft no longer had physical controls -- the controls were holographic projections -- thus, the interior of the hull was completely empty. If a Common Era person came here for the first time, he or she would think this was an empty shell with nothing inside. But Cheng Xin immediately noticed three unusual objects, clearly new additions. These were three circles attached to the hull above the transparent part, colored green, yellow, and red, reminding her of traffic lights from the past. The fleet chief explained:

"Just our side of the meeting. You don't need to worry about Tianming's safety. Sophon has made it clear that even if the red light is lit, only this dinghy will explode; Tianming will not be harmed in any way.

"The red light may be lit during your conversation. However, even if the meeting completes successfully, the Trisolarans may decide, upon review of the conversation record, to turn on the red light. I'm going to tell you the most important part now --" The fleet chief paused again.

He turned around and pointed to the nontransparent part of the hull. Cheng Xin saw a small metallic attachment resembling a weight used on an ancient balance.

"What will be destroyed?" Cheng Xin asked. She wasn't thinking of herself.

"You must remember that the lights will not be used as a traffic light. They may not warn you before deciding that you've stepped over the line. The green light may change to a red light immediately, without going through the yellow light."

"This bomb is controlled by Sophon. It will detonate three seconds after the red light turns on."

Cheng Xin's gaze remained placid. She nodded at him, encouraging him to continue.

"All right. I understand." Cheng Xin's voice was soft, like a passing breeze.

"If I don't return, then you get nothing."

"Other than the contents of the conversation, Sophon may also light the red light if she discovers recording equipment on the dinghy or some means of transmitting your conversation outside the dinghy. You may rest easy on this point. We've examined this dinghy repeatedly for recording devices, and we've eliminated all communications equipment. The navigation system isn't even capable of keeping a log. Your entire journey will be directed by the shipboard AI system, which will not communicate with the outside world prior to your return. Dr. Cheng, please think through what I've said to be sure you understand the implications."

"I'm glad you see. This is what we want to emphasize. Do as they say, and only talk about private matters between the two of you. Do not mention other topics, not even through hints or metaphors. At all times, remember that if you don't return, Earth gets absolutely nothing."

Cheng Xin smiled at the fleet chief. "Thank you. I understand."

"But if I do as you say and return, Earth will still get nothing. That is not what I want."

Five hours later, the dinghy began its journey. The hypergravity of 3G pressed Cheng Xin against the seat -- this was the limit on the acceleration an individual without special training could bear. In a window that showed what was behind her, she saw the immense hull of the terminal station reflecting the fire from her dinghy's drive. The tiny dinghy appeared as a spark flying out of a furnace, but the terminal station rapidly shrank, and soon turned into a tiny dot. Only the Earth itself, still imposing, took up half the sky.

The fleet chief looked at Cheng Xin, but not directly, only at her reflection on the transparent hull. Her image was superimposed against the universe, and her lovely eyes serenely reflected the stars. He seemed to see her as the center of the universe, the stars revolving around her. Once again, he forced himself to not dissuade her from taking a risk. Instead, he pointed behind him. "This is a miniature hydrogen bomb. Under the old measurement system you're familiar with, its yield is about five kilotons. If… it really has to happen, everything will end in a flash. You will not feel it."

Ten minutes later, Cheng Xin got to see a sunrise in space. The Sun slowly rose over the curved edge of the Earth. From such distance, the waves over the Pacific were invisible, and the ocean was like a mirror reflecting sunlight. The clouds appeared as soapy foam over the mirror. From this vantage point, the Sun appeared much smaller than the Earth, like a shining golden egg being birthed by this dark blue world. By the time the Sun had completely emerged from the curved horizon, the side of the Earth facing the Sun turned into a giant crescent. The crescent was so bright that the rest of the Earth merged into dark shadow, and the Sun and the crescent seemed to form a giant symbol hovering in space. Cheng Xin thought of the mark as symbolizing rebirth.

The special team had told Cheng Xin again and again that the flight itself would be routine, no more special than the airplane rides she used to take. The distance between the terminal station and the Lagrangian point was about 1.5 million kilometers, or one hundredth of an astronomical unit. This was considered an extremely short spaceflight, and the craft she rode in was well suited for such brief trips. Cheng Xin recalled that three centuries ago, one of the things that had lured her into aerospace engineering was a great accomplishment by humankind during the twentieth century: fifteen men had managed to step onto the moon. Their voyage had only been a fifth as long as the journey she was about to undertake.

As the dinghy progressed, the lit portion of the Earth expanded. Cheng Xin saw the outlines of the continents, and easily picked out Australia. It resembled a dry leaf floating in the Pacific. The continent was emerging from the shadow, and the terminator was right in the middle of the continent. It was morning in Warburton, and she thought of the desert sunrise seen by Fraisse from the edge of the wood.

She knew that this could very well be her last sunrise. In the upcoming meeting, even if she and Tianming faithfully followed the rules around their conversation, there was a possibility that the distant Trisolarans would not permit her to live, and she wasn't interested in following the rules at all. But she thought everything was perfect; she had no regrets.

Her dinghy swept over the Earth. By the time the curved horizon had finally disappeared over the edge of the viewport, acceleration stopped. As the hypergravity disappeared, Cheng Xin felt as though a pair of arms hugging her tightly had relaxed. The dinghy coasted toward the Sun, and the light from the Sun overwhelmed all the stars. The transparent hull adjusted and dimmed until the Sun was a disc whose brightness was no longer blinding. Cheng Xin reached out to adjust it even more, until the Sun resembled the full moon. She still had six more hours to travel. She drifted in weightlessness, drifted in the moonlight-like sun.

With the engine turned on, gravity returned to embrace Cheng Xin. The deceleration lasted about half an hour before the drive started to pulse for precision position maneuvers. Finally, gravity disappeared again, and everything became quiet.

Cheng Xin glanced at her watch. The voyage had been planned very well. She still had ten minutes before the meeting. The space around her was empty, and she struggled to empty her mind as well. She was preparing herself for the task of memorization: The only thing that could retain anything from the meeting was her brain. She had to turn herself into an emotionless audio and video recorder so that during the next two hours she could remember as much as possible of what she saw and heard.

Five hours later, the dinghy turned 180 degrees and the engine came to life for deceleration. As the dinghy turned, Cheng Xin saw the Sun gradually move away, and then the stars and the Milky Way swept past her vision like a long scroll. By the time the dinghy stopped, the Earth was once again at the center of her view. It now looked about as big as the moon from the surface of the Earth, and the immensity it had displayed a few hours ago was gone. Now it looked fragile, like a fetus floating in blue amniotic fluid about to emerge from the warm womb and be exposed to the frigidity and darkness of space.

This was the Lagrangian point. Here, the dinghy was a satellite of the Sun, orbiting in synch with the Earth.

She imagined the corner of space she happened to be in. Here, the Sun's gravity overcame the Earth's, reaching balance, so this place held an extra measure of emptiness compared to other spots in space. She was in this emptiness of zero, a lonely, independent presence that had no connections to any other part of the cosmos… In this way, she managed to drive her complicated emotions out of her consciousness, until she achieved the blank, transcendent state she wanted.

Not too far ahead of the dinghy, a sophon began to unfold into lower-dimensional space. Cheng Xin saw a sphere about three or four meters in diameter appear a few meters in front of the dinghy. The sphere blocked the Earth and took up most of her view. The surface of the sphere was perfectly reflective, and Cheng Xin could clearly see the reflection of her dinghy and herself. She wasn't sure if the sophon had been lurking inside the dinghy or if it had just arrived.

The reflection on the surface of the sphere disappeared as the sphere turned translucent, like a ball of ice. At times, Cheng Xin thought it resembled a hole dug in space. Next, countless snowflake-like bright spots floated up from deep within the sphere, forming a flickering pattern on the surface. Cheng Xin recognized that this was just white noise, like the random snow seen on a television screen when there was no reception.

Cheng Xin had entertained countless guesses as to what she would see. Maybe she would only have voice and text; maybe she would see a brain floating in nutrient fluid; maybe she would see Yun Tianming whole. Though she believed that this last possibility was practically impossible, she tried to imagine the environment Tianming would be living in. She thought of innumerable scenarios, but none was like what she actually saw.

The white noise lasted about three minutes, and then a scene from several light-years away took its place. It was crystal clear, with no signs of distortion or interference.

A golden field of wheat bathed in sunlight.

The field was about a tenth of an acre. The crop looked to be doing well, and it was time for the harvest. The soil appeared a bit eerie: pure black, and the particles sparkled in the sunlight like innumerable stars. A common shovel was stuck into the black soil next to the field of wheat. It looked perfectly ordinary, and even the handle appeared to be made of wood. A straw hat woven from wheat stalks hung from the top of the shovel -- it looked old and well used, and loose stalks stuck out of the worn rim. Behind the wheat field was another field planted with something green, probably vegetables. A breeze passed through, and the wheat rippled.

Above this dark-soiled scene was an alien sky -- a dome, to be exact, formed of a knotty mess of intertwined pipes, some thick, some thin, all of which were leaden gray in color. Among the thousands of pipes, two or three glowed red. The light from them was very bright, making them appear as incandescent filaments. The exposed portions of these pipes illuminated the fields and apparently provided the source of energy for the crops. Each illuminated pipe only shone briefly before dimming, to be replaced by another pipe that lit up elsewhere. At each moment, two or three pipes were on. The shifting lights caused the shadows in the field to shift constantly as well, as though the sun were weaving in and out of clouds.

Cheng Xin was taken aback by the chaotic arrangement of the pipes. It wasn't the result of carelessness; on the contrary, to create this kind of utter chaos required great effort and design. The arrangement seemed to find even the hint of a pattern to be taboo. This suggested an aesthetic utterly at odds with human values: Patterns were ugly, but the lack of order was beautiful. Those glowing pipes gave the entire knotty mess a kind of liveliness, like sunlight glanced through clouds. Cheng Xin even wondered whether the arrangement was meant to be an artistic representation of the sun and clouds. But the next moment, she felt the arrangement evoking a giant model of the human brain, and the flickering, glowing pipes represented the formation of each neural feedback loop…

A man walked toward her from deep within the wheat field. Tianming.

Rationally, she had to reject these fantasies. A far more likely explanation was that the entire system was nothing more than a heat dissipation device, and the farm fields below only took advantage of the lights as a side effect. Going by appearance alone, and without understanding its operation, Cheng Xin intuited that the system showed a kind of engineering ideal that could not be understood by humanity. She felt mystified, but also mesmerized.

He wore a silver jacket, made out of some kind of reflective film. It looked as old as his straw hat, but was otherwise unremarkable. Cheng Xin couldn't see his pants due to all the wheat, but they were likely made of the same material. As he came closer, Cheng Xin got a better look at his face. He looked young, about the same age as when they had parted three centuries ago. But his physique looked more fit, and his face was tanned. He wasn't gazing in Cheng Xin's direction; instead, he pulled off an ear of wheat, rubbed it in his fingers, blew away the husk, and then tossed the grains into his mouth. He emerged from the field still chewing. Just when Cheng Xin wondered whether Tianming knew she was there, he looked up, smiled, and waved at her.

"Hello!" Cheng Xin said. A wave of emotion that had traversed three centuries surged deep within her consciousness, like a volcano preparing to erupt. But she decisively blocked off all emotional outlets, and silently repeated to herself: Memorize, just memorize, memorize everything. "Can you see me?"

"Hello, Cheng Xin!" he said. In his eyes was pure joy, a very natural kind of joy, like a farm boy working in the fields greeting a girl from the same village who had come back from the city. The three centuries that had passed did not seem to matter, and neither did the several light-years separating them. They had always been together. Cheng Xin had never imagined this. Tianming's gaze caressed her like a gentle pair of hands, and her high-strung nerves relaxed slightly.

The green light above the viewport came on.

"Yes." Tianming smiled and nodded, and tossed another grain of wheat into his mouth.

Tianming seemed taken aback by the question. He waved at the field. "Farming."

"What are you doing?"

"For yourself?"

Tianming was a victor in life.

"Thank you for the seeds you sent," Tianming said. His tone was sincere. "I planted them all. Generation after generation, they've done well. I couldn't get the cucumbers to grow though -- they're tough."

The Tianming in Cheng Xin's memory looked different. During the Staircase Project, he was a haggard, weak, terminal patient; before then, he was a solitary, alienated college student. But though the Tianming of the past had sealed his heart to the outside world, he had also exposed his state in life -- it was possible to tell, at a glance, what his basic story was. The Tianming of the present revealed only maturity. One couldn't read his story at all, though he certainly had stories, stories that probably offered more twists, strange events, and spectacular sights than ten Odysseys. Three centuries of drifting alone in the depths of space, an unimaginable life among aliens, the countless tribulations and trials endured in body and spirit -- none of these had left any mark on his body. All that was left was maturity, a sunlit maturity, like the swaying stalks of golden wheat behind him.

"Of course. How else would I get to eat?"

Cheng Xin chewed over Tianming's words. How does he know that I sent him the seeds? Did they tell him? Or…

"I thought you would have to grow them using aeroculture and aquaculture. I never thought there would be soil on a spaceship."

The green light went off and the yellow light went on.

Tianming bent down and picked up a handful of black soil, letting the particles seep out from between his fingers. The soil sparkled as it fell. "This is made from meteoroids. Soil like this --"

Apparently, Tianming could see the warning as well. He stopped, smiled, and raised a hand. The expression and gesture were clearly intended for those listening in. The yellow light went off and the green light went on again.

"How long has it been?" Cheng Xin asked. She deliberately asked an ambiguous question that could be interpreted many ways: how long he'd been planting; or how long his brain had been implanted in a cloned body; or how long ago the Staircase probe had been captured; or something else. She wanted to leave him plenty of room to pass on information.

Tianming's answer was even more ambiguous. He looked as calm as before, but the yellow light must have terrified him. He didn't want Cheng Xin to be hurt.

"A long time."

"At first I knew nothing about farming," said Tianming. "I wanted to learn by watching others. But, as you know, there are no real farmers anymore, so I had to figure it out myself. I learned slowly, so it's a good thing that I don't eat much."

"The wheat looks really good. Is it time for the harvest?"

Cheng Xin's earlier guess had been confirmed. What Tianming was really saying was very clear: If the Earth still had real farmers, he would have been able to observe them. In other words, he could see the information gathered by the sophons on Earth! This at least showed that Tianming had a close relationship with Trisolaran society.

"Yes. This has been a good year."

"A good year?"

The yellow light came on.

Another guess had been confirmed. The mess of pipes in the ceiling really was some kind of cooling system for the engines. Their light came from the antimatter propulsion system on the ship.

"Oh, if the engines are operating at high power, then I have a good year, otherwise --"

"I know everything. I've always been with you."

Yes, he had always been with her, observing her life through the sophons. He must have seen how she had become the Swordholder, how she had thrown away that red switch in the last moments of the Deterrence Era, how she had endured in Australia, how she had lost her sight from extreme pain, until, finally, how she had picked up that tiny capsule… He had gone through all these trials with her. It was easy to imagine that when he had seen her struggle through her hell from several light-years away, he must have suffered even more pain. If she had known earlier that this man who loved her had crossed the light-years to keep watch over her, she would have been comforted. But Cheng Xin had thought Tianming lost forever in the vastness of space, and most of the time, she had never believed that he still existed.

Tianming's tone was steady and calm, but Cheng Xin's heart quaked.

"All right, let's talk about something else." Cheng Xin smiled. "You want to know what I've been up to? After you left --"

"We can't talk like this," said Tianming, and sighed. Then, with his eyes, he said more: for your sake.

"If I had known…" Cheng Xin muttered, as if to herself.

"You couldn't have." Tianming shook his head.

Yes, it was too dangerous. The yellow light had gone on three times already.

The yellow light came up. Tianming hadn't even said anything. This was a serious warning.

"Hmmm, let me think…" Tianming pondered.

"Then… what about your experience? Can you tell me anything?" Cheng Xin asked. This was a naked attempt at gathering intelligence. But she had to take a step.

Tianming shook his head resolutely. "I can't tell you anything. Absolutely nothing."

Cheng Xin said nothing. She knew that as far as her mission was concerned, she had done all she could. All she could do now was to wait and see what Tianming wanted to do.

The emotions Cheng Xin had pushed deep down surged again. She forced herself to not cry.

Cheng Xin sighed in her heart. Tianming had given up. Her mission would be unfulfilled. But there was no other choice. She understood.

Cheng Xin shook her head. The question was unexpected and incomprehensible. When we were little? But she successfully hid her surprise.

"So many nights, we'd call each other and chat before going to bed. We made up stories and told them to each other. You always made up better stories. How many stories did we tell each other? At least a hundred?"

Once they had set aside the mission, this space that contained them, a few light-years across, became their secret world. Indeed, between the two of them, they needed no language; their eyes were able to say everything they needed. Now that she was no longer so focused on the mission, Cheng Xin could feel even more meaning in Tianming's gaze. She was brought back to her college days, when Tianming had looked at her often in this way. He had been discreet, but her girlish instincts had felt him. Now, his gaze was infused with his maturity, and the sunlight crossed light-years to submerge her in warmth and happiness.

Cheng Xin wanted this silence to last forever, but Tianming spoke again. "Cheng Xin, do you remember how we used to spend our time when we were little?"

Based on the still very limited knowledge humans had of the Trisolarans, sex among them involved the two partners melding their bodies into one. Thereafter, the combined body would split into three to five new lives. These were their descendants, and the "children" referred to by Tianming. But these individuals inherited part of their parents' memories, and were relatively mature at birth, which differentiated them from human children. Trisolarans really didn't have childhood. Both Trisolaran and human scholars believed that this biological difference was one of the root causes of the great differences between their cultures and societies.

"Do you remember any of those stories?"

"Not many. I've moved far away from childhood."

"No, not to myself. I came here, and I felt the need to give this world something. But what? After much thinking, I decided that I could bring childhood to this world, and so I told them our stories. The children here love them. I even put out a collection, Fairy Tales from Earth, which was very popular. This book belongs to both of us -- I didn't plagiarize you; all the stories you told me still have your name in the byline. So you're a famous author here."

"Yes, I think so. A lot." Cheng Xin used to be unable to lie, but she was surprised to find herself performing well.

"But it's not so far away from me. During these years, I've told those stories -- yours and mine -- again and again."

"To yourself?"

"The stories I made up or the ones you made up?"

Cheng Xin became anxious again. She knew now that Tianming had not given up, and the key moment was here. She had to do something, but she had to be very, very careful. Smiling, she said, "Although we can't talk about anything else, surely we can talk about those stories. Those belong only to us."

"Tell the ones I made up. Bring me back to my childhood." Cheng Xin did not hesitate at all. Even she was surprised at how quickly she had caught on to Tianming's plan.

And so, Tianming began to tell the story. His voice was deep and soothing, as though he was chanting an ancient song. Cheng Xin tried hard to memorize, but she was gradually absorbed by the story. Much time passed as Tianming spun his fairy tale. He told three stories, all connected to each other: "The New Royal Painter," "The Glutton's Sea," and "Prince Deep Water." After he finished the last story, the sophon put up a countdown, indicating that they had only one minute left.

"All right. Then let's not talk about anything else. Just the stories. Your stories." Tianming spread his hands and looked up, clearly addressing those monitoring the conversation. His meaning was clear: You shouldn't object to this, right? Everything is safe. Then he turned to Cheng Xin. "We have about an hour. Which story? Hmmm… how about 'The New Royal Painter'?"

"Then let's pick a spot to meet, somewhere other than the Earth, somewhere in the Milky Way."

The moment of parting was at hand.

Cheng Xin awakened from the dream of the fairy tales. Something struck her heart hard, and it was almost unbearable. She said, "The universe is grand, but life is grander. We're certain to meet again." Only when she was done did she realize she had almost repeated Sophon's farewell.

"How about at the star you gave me? Our star." Cheng Xin didn't even need to think.

"All right. At our star!"

The green light went off. Now none of the lights were on. Cheng Xin understood that she was now on the precipice of death. On a ship in the First Trisolaran Fleet several light-years away, the conversation between her and Tianming was being replayed and examined. The red light of death could go on at any moment, and there would be no warning yellow light.

As they gazed at each other across the light-years, the countdown reached zero, and the image disappeared, returning to the snow of white noise. Then the unfolded sophon turned purely reflective again.

After an unknown amount of time had passed, the sophon disappeared. The red light did not come on. The space outside looked the same as before: The blue Earth appeared again in the distance, and behind it the Sun. They were witness to all.

Against the unfolded spherical surface of the sophon, Cheng Xin saw the reflection of her own dinghy and herself. The half of her dinghy facing the sophon was completely transparent, like an intricate locket dangling from a necklace, and she herself was a picture placed in the locket. She was dressed in a snow-white lightweight space suit, and she appeared pure, youthful, beautiful. She was surprised by her own eyes: clear, placid, showing nothing of the surging waves inside her. She felt comforted as she imagined this lovely locket hanging on Tianming's heart.

She felt hypergravity again. The dinghy's thruster was accelerating, and she was going home.

During the few hours of the return voyage, Cheng Xin adjusted the dinghy's hull so that it was completely solid. She sealed herself in and turned herself into a memorization machine. Again and again, she repeated Tianming's words and his stories. The acceleration stopped; the dinghy coasted; the thruster turned around; the dinghy decelerated -- she didn't notice any of it. Finally, after a series of tremors, the door opened, and the terminal station port's light spilled in.

Two of the officials who had accompanied her to the station met her. Their faces were impassive. After a simple greeting, they brought Cheng Xin across the port to a sealed door.

The room was filled with people: All the members of the special team were here. As soon as the two officials who had received her entered, their expressions changed. They now looked as anxious and concerned as the rest.

"Dr. Cheng, you need to rest. Don't dwell on the past. We never held much hope that you'd get anything of use," the PDC official said. And then he gestured for Cheng Xin to enter the sealed door that had just opened.

Cheng Xin had thought this was the exit to the port, but she found herself in an extremely small room. All the walls were made of some dark metal. After the door closed behind her, she couldn't even see the seams. This was not a place of rest. It was simply furnished, with a small desk and a chair. On top of the desk was a microphone. Microphones were rarely seen in this age, and only used for high-fidelity recording. The air in the room had an acrid smell, almost sulfuric, and her skin felt itchy -- the air was clearly heavy with static electricity.

"This is a blind zone for the sophons," someone said to Cheng Xin. Only then did she realize that humans had finally achieved the technology to shield themselves from the ever-present listeners, though it was only possible within extremely confined spaces like this one.

Then the members of the special team left the room one by one. The last to depart was an engineer who explained to Cheng Xin that the walls of the sophon-free room were all electrified, and she should be careful to not touch them.

Only Cheng Xin was left. She sat down at the desk and began to record everything she could remember. An hour and ten minutes later, she was done. She drank a bit of water and milk, took a brief break, and began to record a second time, then a third. When she was ready to record for the fourth time, she was asked to recount the events backwards, with the latest events first. The fifth recording was done under the guidance of a team of psychologists. They used some drug to keep her in a semi-hypnotized state, and she didn't even know what she said. Before she knew it, more than six hours had passed.

The fleet chief said, "Please recite the entirety of your conversation. Don't omit any details that you can recall. Every word may be important."

After she had finished the last recounting, the special team filled the room again. They embraced Cheng Xin and shook her hand. Hot tears flowed, and they told her she had accomplished a heroic deed. But Cheng Xin remained numb, like a memorization machine.

Only when she had returned to the comfortable cabin in the space elevator did the memorization machine in her brain shut off. She became a person again. Extreme exhaustion and waves of emotion overwhelmed her, and as she faced the approaching blue sphere of the Earth, she began to cry. Only one voice echoed in her mind: Our star. Our star…

People only half-believed Sophon. It was likely that only the robot was gone, but a few sophons remained on the Earth and in the Solar System. But it was also possible that she was telling the truth. Sophons were precious resources. What remained of Trisolaran civilization was in a fleet of spaceships, and they wouldn't be able to construct any new sophons for a long, long time. Besides, keeping watch over the Solar System and the Earth no longer had much meaning. If the fleet entered a blind region for the sophons, they might lose the sophons in the Solar System forever.

At that moment, on the surface more than thirty thousand kilometers below, Sophon's house went up in flames. The robot that had been Sophon's avatar was burnt up as well. Before this, she had proclaimed to the world that all the sophons in the Solar System would be withdrawn.

If the last situation occurred, then the Trisolarans and humanity would lose all contact, and once again become cosmic strangers. A three-century-long history of warfare and resentment would turn into so much ephemera in the universe. Even if they were to meet again because of fate -- as Sophon had predicted -- it would be in the distant future. But neither world knew if they had a future.