While the narratives of the previous novels took place over about 200 years, here the narrative begins in the Middle Ages and then extends all the way to millions of years in the future. In order to maintain a character-based POV through this enormous time-span, Liu repeatedly puts his main character (a scientist named Cheng Xin) into hibernation (or subjects her to light speed relativity) in order to have her re-emerge in various eras.
- A preliminary scene involving a mysterious "witch" (set near the fall of Constantinople in 1452) opens the novel. Afterwards, the main narrative begins, taking place roughly in the same time period described in the first two novels. Alongside the Wallfacer Project (as described in The Dark Forest), another strategic group works towards the Staircase Plan, in which a manned investigative probe is sent off to intercept the Trisolarans a couple hundred years before they arrive on Earth. Unfortunately an accident throws the probe off-course.
- In Part 2, the narrative then jumps ahead into the Deterrence Era, in which Earth and Trisolaris maintain a peace held together by the Dark Forest Deterrence Plan (as developed in The Dark Forest). For over 60 years, Trisolaris halts its invasion of Earth and instead works towards a cross-cultural peace. During this time, Luo Ji continues to hold the "trigger" which could spell doom for both Trisolaris and Earth in mutually-assured destruction. Eventually, he is deemed "too old" for the position and a scientist named Cheng Xin (also the main protagonist of the Staircase Plan sequence) is chosen to replace him. During this "hand-over", the Trisolarans take the opportunity to drastically alter the conditions of the peace. When Cheng Xin is faced with capitulation or total self-destruction, she chooses the former. However, at the same time, a deep space vessel discovers "4th dimensional zones", and uses this knowledge to foil Trisolaris' plans. Unfortunately, this solution also exposes Earth to the Dark Forest.
- Part 3 describes the development of various plans designed to prevent the destruction of Earth by interstellar "hunter" civilizations. During this time, a previously-thought "lost friend" makes his return and tries to help humanity make the right choices through veiled parables.
- In Part 4, humanity has settled on the Bunker Plan, in which the population of mankind lives in space cities situated in geosynchronous orbit behind the four outer planets (Jupiter, Uranus, Saturn, Neptune), hoping that the planets' bulk will protect the space cities from a detonation of the Sun. Cheng Xin is awakened from hibernation in order to settle a conflict between a group of ambitious scientists (under her employ) and the greater Solar Federation. In order to avoid civilian bloodshed, she sides with the Federation's more conservative approach.
- In Part 5, the Bunker Plan fails and only Cheng Xin and her assistant "AA" escape the consequences.
- In Part 6, Cheng Xin discovers the remnants of human survivors in "galactic space" and learns much more about the ruthless conflicts being waged amongst the advanced civilizations of the universe. However, due to a chance accident, she is soon thrown millions of years into the future, and then into a parallel "bubble universe". At this point, she is faced (for a third time) whether to choose for her immediate safety or invest in a riskier, but possibly more rewarding, future.
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| Subterranean Press, Marc Simonetti |
Detailed Synopsis
Part 1
- The Death of the Magician: Towards the fall of Constantinople, a prostitute promises Emperor Constantine that she has magical powers. To demonstrate this, she obtains the brain of a guard (without cutting open his skull) and delivers it in a bag. Constantine then tasks her with obtaining the head of the Ottoman sultan, Mehmed II, leader of the Turkish siege forces. She fails. Later, it is revealed that in order to perform her "miracles", she had gone into a ruined minaret. Somehow, the top of the minaret had briefly disappeared and then re-materialized. From May 3 to May 28, a "high dimensional fragment" had intersected with Earth, allowing for "magic" to exist. The female "magician" loses her powers with the departure of the fragment. Constantinople falls the next day.
- Year 1: The Option for Life: Ye Wenjie's daughter Yang Dong becomes despondent after her faith in physics is broken by the sophons' interference. Additionally, she has discovered that her mother has betrayed humanity to the Trisolarans. On one of her last days at her physics lab, a scientist shows her a computer simulation of the development of Earth from its beginnings. She learns that the current state of Earth's atmospheric and geologic conditions has been achieved with influence from life's appearance on the planet, and that if life had never surfaced, then the Earth would have become a desert wasteland. She wonders if the same holds true for the entire universe, that nature is not "natural" at all.
- Year 4: Yun Tianming: During a student outing, a shy young man named Yun Tianming becomes infatuated with a female colleague named Cheng Xin, and maintains feelings for her without ever acting upon them. Years later, he is diagnosed with terminal cancer. Shortly afterwards, euthanasia is legalized. He decides to end his life, but before he undergoes the procedure, he decides to spend a recent chance windfall on Cheng Xin by buying her a star through the new Stars My Destination Project, a UN resolution to auction off ownership rights of distant stars in order to raise money for its own political ends.
- Year 4: Yun Tianming: Yun Tianming buys and deeds a star to Cheng Xin, and asks that she not be informed that it was from him. Afterwards, he schedules his euthanasia appointment. However, just before he is injected with the lethal toxin, Cheng Xin bursts in and halts the procedure.
- Years 1–4: Cheng Xin: A bright young aerospace academy graduate named Cheng Xin is chosen to join the PIA, an intelligence group designed to form strategies against the Trisolarans. When Wade, the head of the PIA, proposes to send a probe out to intercept and investigate the approaching Trisolaran fleet, Cheng Xin suggests the use of sequenced, pre-positioned nuclear explosions to push forward a probe propelled by radiation sails (the "Staircase Plan"). However, the UN eventually feels that such a probe would not be very useful. Wade then decides to send a live human out (in a hibernated state) to intercept the Trisolarans, with the intention of having this agent be captured. In this way, they may be able to engage in some form of espionage against the "transparent" Trisolarans. (Prior to the Crisis Era, hibernation technology had been suppressed for fear of tempting people to escape to a future in which immortality ("death's end") had been achieved. However, once the Trisolaran threat appeared, such concerns were no longer valid, and hibernation became commonplace.)
- Years 1–4: Cheng Xin: Cheng Xin learns that, due to weight restrictions,it is impractical to send hibernation apparatus into space. She proposes that the PIA "flash-freeze" a volunteer and assume that the Trisolarans have the technology to safely reawaken a "dead" human (which they would hopefully value as a live prisoner for study). Later, another weight restriction appears: the capsule will only be able to carry half a kilogram of weight. Wade suggests that only a frozen brain be sent.
-
Years 1–4: Cheng Xin: In order to find a suitable brain for the
mission, the PIA press for euthanasia to be legalized. Cheng Xin receives
the deed to her new star, but has no idea who it might be from. She also
hears from a mutual classmate that Yun Tianming has terminal lung cancer.
She decides to fly to China to ask him to volunteer his brain for the
mission. When Yun Tianming realizes that Cheng Xin had only interrupted his
euthanasia procedure in order to get his permission to send his brain to the
Trisolarans (and not because she loved him), he reacts with understandable
bitterness. Nonetheless, he agrees to put off euthanasia and volunteers for
her mission.
- Years 5–7: The Staircase Program: When Wade informs Cheng Xin that Yun Tianming had been the one to give her her star, she tries to stop the procedure but is too late: Yun Tianming's brain has already been extracted and frozen. Cheng Xin goes into hibernation so that she can monitor the project when the probe intercepts the Trisolarans. The Staircase probe is soon launched, but weeks later an accident causes the probe to head off course, and missing the Trisolaran fleet entirely.
Part 2
- Year 12: Bronze Age: With the Trisolaran conflict now over, the Bronze Age is told to return home as heroes. However, when they arrive on Earth, they are all arrested for treason and murder.
- Year 13: Trial: During the Bronze Age trial, it is revealed that the ship had quickly descended into totalitarianism and cannibalism (of the bodies of the Quantum crew). Near the end of the investigation, a Bronze Age communications officer manages to send a message to Blue Space, warning them of what awaits them on Earth if they return. The Earth ship Gravity (accompanied by two Droplets) heads off in pursuit of Blue Space, although it will take 50 years for them to intercept it.
- Year 61: The Swordholder: With new technology obtained from the Trisolarans, interstellar real estate gains great monetary value. In order to buy her now very valuable star, the Earth government awakens Cheng Xin from hibernation. She discovers that all men have now become feminine, and that the surface of the Earth has returned to a pre-Industrial state of forestry (although gigantic "leaf cities" dot the surface). Cheng Xin elects to keep her star, and hires an assistant named AA to help her manage it as a company. One day, Cheng Xin is lured to a forest area where a reawakened Wade tries to kill her for obstructing his "Swordholder" plan. Fortunately, his attempt fails and Wade is arrested.
- Year 61: The Swordholder: Cheng Xin recovers from Wade's attack and begins to appreciate the modern art scene for its serenity. She is stunned to learn that the artists are Trisolaran. During the Deterrence Era, the Trisolarans had begun to value human arts. Eventually they began imitating Earth culture themselves. However, they never reveal much about their own culture to the humans.
- Year 61: The Swordholder: Cheng Xin is invited to meet Sophon, an android Trisolaran representative. After a serene tea ceremony, Sophon implies that Cheng Xin should become a "sympathetic" Swordholder. Due to the self-destructive, genocidal implications of the Dark Forest Deterrence plan, only Luo Ji himself had been deemed qualified to insure that such a threat truly existed. His role had become known as the "Swordholder". After her meeting with Sophon, Cheng Xin is also visited by other Swordholder candidates who insist that she is too soft-hearted to handle the role. In the end, the public reject the "hard-liners" and choose Cheng Xin to take the position.
- Year 62: Gravity, in the Vicinity of the Oort Cloud: The Gravity eventually begins to catch up to the Blue Space. However, unexpectedly, they reach an area of space in which instantaneous communications with Earth through the sophons is no longer possible. These "Sophon-Blind Regions" apparently occur throughout the universe, and seem to be zones created by intelligent civilizations (perhaps to "hide" the forest around them).
- Year 62: Gravity, in the Vicinity of the Oort Cloud: The crew of the Gravity begin seeing strange phenomena, such "ghosts" of Blue Space crewmen, or empty voids appearing in the middle of the ship bulkheads. One navigator reports feeling claustrophobia after having experienced an "openness" unknown to man. However, these concerns become unimportant when the Droplets move to attack the two human ships.
- Year 62 November 28, 4:00 P.M. to 4:17 P.M.: Deterrence Center: The Swordholder's trigger is located deep underground so that it is inaccessible to hard-line terrorists. However, because the Trisolarans still maintain Droplets in the Solar System with the capability to destroy the gravitational signal stations, a Swordholder has only 10 minutes to pull the trigger if the Trisolarans decide to break the peace. Now elected to the Swordholder position, Cheng Xin enters a tomb-like facility located 45 km below Earth's surface.
- Year 62 November 28, 4:00 P.M. to 4:17 P.M.: Deterrence Center: After half a century of vigilance, Luo Ji passes the Swordholder "hilt" (trigger device) to Cheng Xin and departs.
- The Final Ten Minutes of the Deterrence Era, Year 62 November 28, 4:17:34 P.M. to 4:27:58 P.M.: Deterrence Center: 5 minutes into Cheng Xin's stint as the new Swordholder, she learns that Trisolaran Droplets are heading towards the gravitational wave transmitters intending to destroy them. Faced with putting an "ending period" to the entire history of humanity, Cheng Xin decides to throw away the trigger. The Earth-based gravitational signal transmitters are destroyed by the Droplets and mankind's ability to send "spells" into deep space is terminated (however, the ship Gravity also possesses a gravitational transmitter).
- First Hour: A Lost World: Cheng Xin emerges on the
surface and runs into AA, who has not yet realized that the Trisolarans have
defeated Dark Forest Deterence.
-
First Hour: A Lost World: The Trisolaran android Sophon
meets Cheng Xin and AA at one of the Droplets' impact craters (where a
gravitational transmitter had just been destroyed) and mocks her, telling
her that they had expected her to fail (and in fact they had most feared
Wade becoming the Swordholder). When AA mentions the gravitational
transmitter on Gravity, Sophon tells them that Gravity has
already been destroyed.
-
Day 60: A Lost World: A 2nd Trisolaran fleet is
detected on its way towards the Solar System. Unlike the first fleet (which
required 450 years of travel time), this fleet only requires 1 year, due to
advancements in Trisolaran technology. However, it does require a few years
to reach Earth, since after coming out of "light-speed" it must use
conventional propulsion to navigate inside the solar system.
-
Day 60: A Lost World: Sophon tells mankind that, out of
respect, the Trisolarans will allow humanity to live primitive lives in
Australia and on a part of Mars. When mankind resists, a Droplet destroys
several major cities. Afterwards, the mass emigration to Australia
begins.
- Year 2: Australia: After the emigration is complete, Sophon announces that electricity in Australia will be turned off for three months. During that time, she expects that mankind's population of 4 billion will be reduced to a more manageable 50 million due to starvation and cannibalism.
-
The Final Ten Minutes of the Deterrence Era, Year 62 November 28, 4:17:34
P.M. to 4:27:58 P.M.: Gravity and Blue Space, Deep Space:
Somehow, using unknown technology, the Blue Space is able to destroy
the Droplets targeting them before they are destroyed. The two ships
rendezvous and Chu Yan, captain of the Blue Space, explains that a
Trisolaran fleet has launched towards Earth and that the Trisolarans are
likely exterminating mankind as they speak. The two crews vote to activate
their gravitational transmitter, knowing that they are putting both
Trisolaris and Earth under a spotlight in the Dark Forest. The coordinates
to Trisolaris' location is sent out in an omnidirectional
interstellar broadcast.
- Year 2, The Morning After the Great Resettlement, Australia: The Trisolarans detect Gravity's transmission and immediately abandon any further plans for Earth.
- Day 1–Day 5, Gravity and Blue Space, Deep Space Beyond the Oort Cloud: Chu Yan explains to Guan Yifan (a scientist from Gravity) that the crew of Blue Space have discovered that the two ships have been traveling through a 4th-dimensional fragment about the size of the Solar System. Intersections with points from this fragment cause spherical "warp zones" to appear, which allow trips in 4th dimensional space. By this method, the Blue Space had been able to approach the Droplets from a 4th dimensional location and destroy them. The two crews then conduct additional missions into the 4th dimension and soon discover that the fragment contains sentient 4th dimensional structures (including a gigantic Ring), and that the fragment is slowly dissolving for some reason. As the 4th dimensional "tombs" are exposed to 3-dimensional space, they disintegrate. After leaving the 4th-dimensional region, a small ark of a couple hundred people head back towards the Earth, while the rest continue into deep space on Gravity and Blue Space.
Part 3
- Year 7: Cheng Xin: With the Trisolarans gone, mankind returns to a form of normalcy. Some try to maintain a sense of optimism by even questioning the validity of the Dark Forest theory.
- Year 7: Cheng Xin: One evening, Cheng Xin is alerted to a glowing star in the sky. It soon fades away. She realizes that Trisolaris has been destroyed, and the Dark Forest theory is real. Records show that one of the Trisolaran suns had been destroyed by a "photoid" traveling at light speed.
- Year 7: Sophon: Cheng Xin and Luo Ji are invited to meet Sophon for a "friendly" meeting. She reveals that Earth may have more time left because Trisolaris looked "more dangerous". Luo Ji asks if there is some way that Earth can signal their "harmlessness" to the Dark Forest with some kind of "cosmic safety notice" (stating that mankind is harmless, or that mankind has "self-mutilated" itself into a state of harmlessness). Sophon says yes, but refuses to say how.
- Year 7 Sophon: Cheng Xin descends into a depression. However, before she takes a fatal pill, Sophon contacts her and tells her that she is leaving Earth. She also tells Cheng Xin that Yun Tianming would like to see her.
- Year 7: Yun Tianming: Cheng Xin is brought to a Lagrange Point between Earth and the Sun in a small space "dinghy". A sphere appears displaying a video-feed of a healthy Yun Tianming (apparently in a clone body) in a field, farming. During the conversation, Yun Tianming is prevented from giving any explanation of his relationship with the Trisolarans, due to an explosive device in Cheng Xin's dinghy controlled by the Trisolarans. However, he does tell Cheng Xin three "stories" which he passes on as "childhood memories".
- Year 7: Yun Tianming’s Fairy Tales:
- “The New Royal Painter”: When the King of the Storyless Kingdom decides to give the throne to Princess Dewdrop, her nefarious brother Prince Ice Sand becomes angry and hires a magic painter named "Needle-Eye" to kill the royal family. He does this by painting their portrait, after which their real forms disappear. However, before Princess Dewdrop is killed, Needle-Eye's old master, Ethereal, gives her a protective umbrella (that must be constantly spun). He tells her that she must seek out her kindly other brother, Prince Deep Water. Prince Deep Water is immune from Needle-Eye's magic because Needle-Eye can only pant in the "Western style".
- “The Glutton’s Sea”: A soldier named Long Sail takes Dewdrop on a journey to seek out her brother Deep Water. On the way, Long Sail tells Dewdrop that the Storyless Kingdom is actually an island surrounded by glutton-fish, which can chew boats to pieces. This glutton sea isolates the island from contact with the outside world.
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“Prince Deep Water”: At the shore of the
Storyless Kingdom, Long-Sail and Dewdrop see the giant figure of Prince
Deep Water on Tomb Island, located some distance away. They use "magic
soap" to create a layer of bubbles which prevent the glutton fish from
destroying their boat as it crosses the glutton sea. As they approach Tomb
Island, Prince Deep Water appears to shrink into normal size. It turns out
that the Prince does not obey the laws of perspective: his size appears
the same no matter what distance he is being viewed from (and therefore
looks like a "giant" from a long distance in relation to the smaller
objects seen in perspective, such as as seen in ancient paintings from
Egypt, China and India). When Prince Deep Water returns with his sister to
the Storyless Kingdom, Needle-Eye is unable to paint him into
non-existence because he only knows how to draw in perspective. Deep Water
kills Ice Sand and becomes the king, while Dewdrop and Long-Sail leave the
Storyless Kingdom in search of adventure.
- Year 7: Yun Tianming’s Fairy Tales: The IDC try to interpret Yun Tianming's stories for clues to their salvation, but nothing concrete emerges. The Solar Federation eventually comes up with their own solution, the Bunker Plan, which involves the construction of geosynchronous space cities situated "behind" Jupiter, Saturn, Uranus and Neptune (when seen from the Sun). This way, if a Dark Forest attack destroys the Sun, these cities will be shielded from the blast by the large planets.
- Year 7: Yun Tianming’s Fairy Tales: One day AA demonstrates that soap bubbles can be used to propel a paper boat through water. This leads to the idea of "curvature propulsion" for light-speed travel, in which an artificial imbalance in time-space curvature can be used to propel a craft forward. Space is curved, and if an area behind a ship is "flattened", the area in front will naturally increase its curvature to compensate, thereby "dragging" a ship forward. This leads to the Lightspeed Spaceflight Plan, in which mankind might simply flee the Solar System before a Dark Forest strike occurs.
- Year 7: Yun Tianming’s Fairy Tales: Further leaps in deduction lead Cheng Xin and the IDC to deduce that Yun Tianming's stories hint at the concept of creating a "virtual event horizon" around the solar system ("glutton sea"). This could be done by lowering the speed of light in the region to below the velocity necessary to escape the Solar System. In effect, this would be a cosmic safety notice, both hiding the Solar System and signalling that it was harmless (by disguising it as a black hole). This idea becomes known as the Black Domain Project.
- Year 8: Fate’s Choice: When a planetary alert system is first turned on, it reports that a photoid attack is inbound. Mankind goes into a panic and every ship available tries to take off in order to escape the ensuing destruction (in the hopes of reaching Jupiter). However, the alert turns out to be a false alarm.
- Year 8: Fate’s Choice: Two days before the false alarm; Observation Unit #1: Astronomers detect "soap bubbles" in space, apparently trails left by Trisolaran ships using curvature propulsion. For this reason, the Lightspeed Spaceflight Plan is officially abandoned due to its tendency to attract attention in the Dark Forest. Lightspeed research is also discouraged because mankind has by now realized that deep space is not particularly safe.
- Year 8: Sun-Earth Lagrangian Point: During a scaled-down test of the Bunker Plan, Cheng Xin is among the volunteers aboard a ship positioned behind an asteroid intended to represent Jupiter, while a large explosion occurs on the other side. During the test, Wade convinces Cheng Xin to give him all of her assets and power (gained from the star which Yun Tianming had given her long ago) so that he can secretly continue research into lightspeed technology (which Cheng Xin supports). Cheng Xin complies, but Wade is also instructed to consult her if any possible harm to the human race may result from his work. Afterwards, Cheng Xin and AA go into hibernation to be awakened when the project is a success (or she needs to be consulted).
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| Subterranean Press, Marc Simonetti |
- Bunker World: Cheng Xin is reawakened 62 years later. One of her old associates, Cao Bin, gives her a tour of Bunker World, which is comprised of 164 space cities situated behind the four outer planets. Due to the limited resources, suburban life inside the spinning cities has returned to something much closer to 21st century life, with a wide range of social classes.
- Lightspeed II: One structure, Lightspeed II, had been constructed in order to enclose a miniature black hole (as part of research into the Black Domain Plan to slow down the speed of light). However, one scientist had fallen into the black hole and become trapped at its event horizon. Eventually, the Lightspeed II had been abandoned.
-
Halo City: Cheng Xin is brought to Halo City, where
Wade has finally taken the first concrete steps towards perfecting curvature
propulsion. However, the Federation has now put Halo City under a blockade
and demands that the work stop and the city surrender. Wade however, has
amassed an army equipped with antimatter weapons. Not only that, but he also
has agents in the other Bunker cities similarly equipped. Cheng Xin realizes
that Wade is willing to go to war with the rest of humanity in order to
continue his quest for the stars. As promised in their meeting during the
scaled-down Bunker Plan test, Wade has awakened Cheng Xin to decide on the
next course of action. Unwilling to sacrifice the civilians of Bunker World,
Cheng Xin orders Wade to disarm and surrender. Wade complies and is
eventually executed. Cheng Xin and AA decide to go back into hibernation to await
the Dark Forest strike still to come.
- Year 67: Orion Arm of the Milky Way: An alien observer named "Singer" detects the lightspeed trails of the Trisolarans near Trisolaris. However, Singer also sees that the system has already been "cleansed". Singer then detects the communications between Trisolaris and Earth. It sends a "dual-vector foil" towards the Solar System in order to cleanse it as well.
- Year 67 Halo: Cheng Xin and AA are awakened from hibernation aboard the Halo. An aged Cao Bin tells them that a Dark Forest strike is on the way, and that the Bunker Plan will not save humanity.
- Year 66: Outside the Solar System: A year before Cheng Xin's reawakening from hibernation, the space alert system detects a foreign object approaching the Sun, apparently of alien design. When a ship goes out to investigate it, it appears to be a glowing "slip of paper" (a credit-card-sized plane with no thickness). However, the glow soon fades away and the rectangular 2-dimensional object begins dissolving the surrounding 3-dimensional space into 2-dimensions (much like Needle-Eye painting the royal family in Yun Tianming's fairy tale). The plane continues to expand like a whirlpool funnel, rendering everything caught in its influence into lifeless 2 dimensions. The astronauts quickly realize that the entire Solar System will eventually be consumed by this expanding plane in 8-10 days, and in order to escape the pull of this 2-D plane, lightspeed must be reached. Thus mankind had failed to correctly interpret Yun Tianmimng's true message: Escape being "painted" into non-existence by achieving lightspeed using curvature propulsion.
-
Year 68: Pluto: The Federation asks Cheng Xin and AA go to Pluto
so that they can move objects from an Earth Civilation Museum into space so
that they might be recoverable someday by aliens (even after conversion to
2-dimensional space). There, they are greeted by Luo Ji in an underground
complex. The purpose of the complex is to act as a "tombstone" for humanity,
with words carved in the cavern walls. The three of them begin collecting
famous paintings from the museum storage area (including "Starry Night" and
the "Mona Lisa").
-
Year 68: The Two-Dimensional Solar System: Back on the surface
of Pluto, Cheng Xin, AA and Luo Ji watch the rest of the Solar System become
two-dimensionalized by the plane. When Cheng Xin and AA take off in the
Halo in order to disperse the museum artifacts into space, Luo Ji
elects to remain behind in the museum to be near the "Mona Lisa" (a painting which once connected him to his wife). Once off the planet, Luo Ji
contacts Cheng Xin and AA and tells them that the Halo is equipped
with a curvature propulsion (the only one in the Solar System), and that
they can escape the 2D plane. The true purpose of Cheng Xin and AA's trip to Pluto was to pick up Luo Ji and then escape the Solar System in the Halo. However, Luo Ji has decided to remain behind. He also informs Cheng Xin that curvature
propulsion effectively slows down the speed of light in its "backwash", and
that a fleet of lightspeed ships could theoretically create a Black Domain
to protect the Solar System. However, because Cheng Xin had stopped Wade's
takeover, this had not been discovered in time. Finally, Luo Ji also advises
Cheng Xin to consider seeking out the Trisolaran fleet which had fled into deep
space after their planet had been destroyed. After Pluto (and Luo Ji) are
consumed, Cheng Xin tells the Halo AI to head toward the star which
Yun Tianming had bought for her long ago.
- Year 409, Our Star: 52 hours later by Halo time (and 286 years by Solar System time) the Halo reaches Cheng Xin's star ("Our Star"). Eight days later they reach a "Blue Planet" using fusion propulsion. As they approach, the Halo detects a radio signal. When they land, they are greeted by Guan Yifan, the astronomer from the Gravity, who is still alive due to hibernation, and had been visiting the planet on a research expedition. Guan Yifan explains that long ago the Gravity and Blue Space had discovered worlds to settle, and even developed curvature propulsion on their own. In fact, life on the three human worlds of the "Galaxy Era" is proceeding well. He also explains that the two-dimensionalization of the Solar System has removed that area of space from visual detection, and now exists only as a gravitational effect (a condition which possibly explains dark matter).
- Year 409, Our Star: When Guan Yifan is alerted to the presence of visitors on the Gray Planet (the other planet orbiting Cheng Xin's star), he decides to investigate in his ship Hunter, and brings along Cheng Xin (who hopes to reunite with Yun Tianming somehow).
- Year 409, Our Star: On the way, Guan Yifan tells Cheng Xin that the universe is a cosmic battlefield, with civilizations waging war using the laws of physics as weapons. For this reason, the initial state of the universe, a 10-dimensional "Eden", has over billions of years gradually been dissolved into lower and lower dimensional levels (through weapons such as the 2D plane which had destroyed the Solar System). Additionally, reduced lightspeed regions are used to create black hole "walls".
- Year 409, Our Star: On Planet Gray, they discover that some visitors have created "death lines", essentially black holes in the shape of long columns. These visitors, "Zero-Homers" ("Resetters") hope that when the universe is completely destroyed, a new, "reset" universe will come into being as another Eden.
- Year 409, Our Star: On the way back to the Blue Planet, AA contacts the Hunter and informs Cheng Xin that Yun Tianming has arrived, drawn by an automatic signal from the Halo. Cheng Xin and Guan Yifan begin descending to the Blue Planet in the Hunter's shuttle, but the death lines on the Gray Planet rupture (inadvertently caused by the arrival of Yun Tianming's curvature propulsion ship in the system). This traps the Hunter shuttle in a lightspeed orbit around the Blue Planet, enclosed in a localized black domain. Cheng Xin and Guan Yifan are forced to go into temporary hibernation due to the lack of oxygen in the shuttle. Due to the effects of special relativity, eons pass by on the planet while only days pass inside the shuttle.
- When Cheng Xin and Guan Yifan come out of hibernation they bring the shuttle out of its lightspeed orbit. When they land on Planet Blue they learn that 19 million years have passed. However, in the bedrock, a partial message from AA and Yun Tianming can be read, describing the happy life they had lived, and hinting at some kind of "gift". A door then appears in mid-air, apparently designed to activate when recognizing the body signatures of Cheng Xin and Guan Yifan. They step through the door.
- Cheng Xin and Guan Yifan arrive in a pastoral landscape occupied by a white farmhouse. Sophon emerges from the house and informs them that they are in Yun Tianming's "gift", a self-sufficient "bubble universe" (Universe 647) maintained outside of the main universe through Trisolaran technology. Also included is a database containing the history, arts and sciences of Earth and Trisolaris. As per Yun Tianming's design, time passes at a different rate in Universe 647, and in 10 years the greater universe will have undergone another Big Bang reset, at which point Cheng Xin and Guan Yifan can return to a new and (hopefully) Edenic Age.
- A year passes, during which time Cheng Xin begins writing a book titled A Past Outside of Time. One day, Universe 647 receives a broadcast from the greater universe. A group called "The Returners" claims that, due to the creation of many other self-contained bubble universes like Universe 647, the greater universe no longer has enough critical mass to contract and reset. The greater universe will essentially expand until it completely dissipates into a heat death state. The Returners ask that all of the "escapees" return so that the mass regained will allow a Big Crunch to proceed. Although Cheng Xin and Guan Yifan could live comfortably in Universe 647 no matter what happens to their original universe, they elect to return for the sake of the greater universe's future.
- In preparation for their return, Cheng Xin and Guan Yifan prepare a "message in a bottle" (computer database) containing the knowledge of Trisolaran and Earth civilization. This bottle will remain behind in Universe 647, but after the next reset, the bottle will automatically return to the newly-reborn universe, hopefully allowing for a rebirth of the past. After all of the earth and metal comprising Universe 647 is funneled through a door leading back into the greater universe (restoring its mass), Cheng Xin and Guan Yifan pass through as well, but not before also leaving behind a small, self-sufficient "aquarium" containing some fish.
