Plot
Common Era and Crisis Era
The story begins during theDeterrence Era and Broadcast Era
At the end of ''The Dark Forest'', the Trisolaran invasion was averted owing to Luo's threat of Mutually Assured Destruction (MAD), which involves broadcasting the position of the planet Trisolaris across the universe, thereby attracting the attention of hostile alien races. This system operates on the assumption that alien forces would cleanse such broadcast coordinates. In the event of such a broadcast, Earth would be exposed as well due to its (4.5 light year) proximity to Trisolaris and prior messages exchanged, revealing their relative location. Luo is appointed to be the first Swordholder, the person responsible for launching the broadcast in the event of any further Trisolaran aggression. With safety restored, the defecting ships ''Bronze Age'' and ''Blue Space'' are seemingly invited to return. However, upon the return of ''Bronze Age'', its crew is imprisoned for crimes against humanity. The lieutenant commander in charge of targeting systems and attack patterns of ''Bronze Age,'' warns ''Blue Space'' not to return, so the human ship ''Gravity'' and two Trisolaran droplets join forces to chase after ''Blue Space''. Fifty years pass. Cheng wakes up from hibernation due to her possession of DX3906, whose planets are discovered by an astronomer named AA. Cheng and AA start a company together, and Cheng becomes the leading candidate for the next Swordholder, in part due to her past experience and her status as somebody who owns another world. Wade desires the position and attempts to murder Cheng, but is arrested and thrown in prison. Right after Cheng's inauguration, the Earth is attacked by Trisolaran droplets, and humanity's gravitational-wave transmitters are destroyed, with the Trisolarans correctly guessing that Cheng would not send the MAD broadcast. At the same moment, the two droplets working with ''Gravity'' attempt to destroy ''Gravity'' and ''Blue Space''. However, the crew-members of ''Blue Space'' have discovered a fading "four-dimensional fragment" in space, which they exploit in order to destroy the two droplets and capture ''Gravity''. The crew-members of the two ships make peace, and decide to send out the MAD broadcast using ''Gravitys antenna. Afterward, ''Gravity'' joins ''Blue Space'' in escaping the solar system. The Trisolarans, through Sophon, a diplomatic link, propose that the entire human population move to Australia and Mars, where they are to be systematically starved to reduce their numbers to manageable levels. The Trisolarans attack three cities in Asia, North America, and Europe. After the attacks, the people of Earth flee to Australia. Australia becomes overpopulated. Sophon destroys all sources of electricity. When questioned about food sources, she insinuates that cannibalism would occur. Upon detecting the MAD broadcast, the Trisolarans abandon their invasion of the Earth. A few years later, as humanity recovers, one of Trisolaris's three suns is struck by a relativistic "photoid" launched by unspecified aliens, leading to the planet's utter incineration. It is understood that sooner or later, the Solar System will suffer a similar attack. The remnant Trisolarans reveal that they have Yun in their custody, and allow a single, heavily supervised tele-conference between Yun and Cheng. Yun, having been treated by the Trisolarans as an honored guest, and granted access to the Trisolaran data-banks, delivers a complex fairy tale which contains three cosmological secrets, two of which are subsequently deciphered by the human council: that light-speed travel can be attained by warping space through "curvature propulsion", and that it is possible for a civilisation to reduce the speed of light so that they cannot escape their own star system, thereby forming a "black domain" which no one will attack as its inhabitants cannot affect the space outside.Bunker Era
Humanity decides to heavily invest in space cities possessing artificial light sources, which can hide in the shadow of the solar system's gas giants to escape any photoid attack against the sun. As time goes on, nearly the entire Earth is evacuated. Research into curvature propulsion is banned owing to resentment from the populace, who regard the technology as an escape hatch for the ultra wealthy, and owing to the discovery that such propulsion creates permanent rifts in spacetime. Cheng strongly disagrees with this policy, and accepts a request by Wade, now out of prison, to transfer all of her private wealth to him, so that he may assemble a secret research team. Cheng hibernates for sixty years, and is woken at Wade's request after the latter's adherents get into an armed standoff with the government. Worried over the danger to civilians caused by Wade's new antimatter bullets, Cheng demands Wade's surrender, reminding him that she has final say in the venture, and Wade reluctantly orders his security forces to stand down. Contrary to expectations, the government shows no mercy to Wade on account of either his voluntary surrender, or the quality of his research. Wade is executed, to Cheng's dismay, and Cheng, feeling that her life has no direction, hibernates for another sixty years with AA before waking up to the news that the alien strike has arrived. However, the space cities are totally useless: the attack has come in the form of an object which collapses 3D space into two dimensions. The existence of such weapons was the third secret in Yun's story which the interpreters had neglected. The only way to survive is either to flee at light speed, or to have re-engineered one's species to exist in the 2D plane. The entire solar system is flattened and killed, with all ships being sucked in, but Cheng and AA escape using a curvature propulsion ship built in secret by Wade's associates after his death.Galaxy Era
Cheng Xin and AA travel at light speed to Planet Blue, one of the two planets orbiting DX3906. The journey takes 287 years, but from their perspective, only 52 hours in light speed was spent. There, they encounter Guan Yifan, a civilian cosmologist of ''Gravity'', who explains that the crew of his ship and ''Blue Space'' went on to develop curvature propulsion and colonize four planets (in different systems). However, one of those planets became fearful of detection, and placed itself within a Black Domain. Cheng Xin and Guan Yifan fly to the nearby Planet Gray to investigate signs of alien activity, whereupon they discover Death Lines (similar to black holes) which were laid down by a faction of aliens purposely trying to accelerate the ruin of the universe. At this point, Guan Yifan explains the larger picture to Cheng Xin: the universe is slowly being torn apart by galactic warfare. As a young universe, the universe existed in 10D, and the speed of light was near infinity, meaning light could illuminate any place in the universe in a Planck Time, but as time went on, galactic civilizations continually re-engineered themselves to occupy one fewer dimension, and then tore apart the topmost dimension as a way of killing their enemies. Likewise, some civilizations created black holes to serve as shields against foreign attacks, but this led to the reduction of light speed, owing to the disruption of spacetime. As Cheng Xin and Guan Yifan fly back to Planet Blue, they are notified by AA that Yun Tianming has arrived. Cheng Xin is overjoyed that they will finally reunite. However, the Death Line suddenly expands and traps their ship within a low light speed black hole that renders their electronics useless. Guan Yifan tells Cheng Xin that modern spaceships are equipped for this, but booting the neural computer will take sixteen days. They hibernate to survive the boot time, but awaken to discover it has worked and they can descend onto Planet Blue. When they are released, they discover that 18 million years have passed in the external universe, and that the speed of light has been reduced by a factor of 10,000. They find a message revealing that AA and Yun Tianming lived a happy life together, and prior to dying left behind a gift for Cheng Xin and Guan Yifan: a pocket universe measuring one cubic kilometer, made with Trisolaran technology, containing an idyllic farmstead to which Cheng Xin and Guan Yifan can retire with the company of Sophon. They wait for the main universe to die and be reborn as the Garden of Eden. After living there for some time, Cheng Xin and Yifan receive an alien message aimed at all denizens of micro-universes in all languages including Earth's and Trisolaran's, stating that the presence of micro-universes deprives the main universe of mass, disrupting its possibility of eternal cycles of expansion, collapse and rebirth. Cheng Xin, accompanied by Yifan, and wearily reflecting on her lifetime of moral duty, disassembles the objects of the micro-universe and steps back with them into the dying main universe, leaving behind a message in a bottle and also a fishbowl for the reborn universe to uncover.Characters
* Cheng Xin (程心) – Aerospace engineer from the early 21st century, second Swordholder * Yun Tianming (云天明) – Cheng Xin's university classmate who has a romantic interest in her; his brain is sent into space and captured by the Trisolaran fleet, who manage to clone his body and return him to life. * Thomas Wade (托马斯·维德) – Former CIA Chief, most effective candidate for Swordholder, develops curvature propulsion prototype. * Ai AA (艾AA) – Ph.D. in astronomy from the Deterrence Era, Cheng Xin's friend and traveling companion * Luo Ji (罗辑) – Cosmic Sociologist, first Sword-holder *Neil Scott – Captain of ''Bronze Age'' *Sebastian Schneider – Lieutenant commander of targeting systems and attack patterns aboard ''Bronze Age'' *Captain Morovich – Captain of ''Gravity'' *Chu Yan – Captain of ''Blue Space'' * Sophon (智子) — Trisolaran android, controlled by sophons, who provides a diplomatic and communicative link between Earth and Trisolaris * Guan Yifan (关一帆) – A civilian astronomer from ''Gravity'' * Yang Dong (杨冬) –Trilogy
The additional books in the ''Awards
References
External links
* {{authority control 2010 science fiction novels Novels by Liu Cixin Alien invasions in novels Cryonics in fiction 2010 Chinese novels