The novel contains elements of historical fiction (in particular about the Chinese Cultural Revolution), first contact narrative, mystery, espionage and fantasy (as portrayed in a cyberpunk videogame). It also touches on various scientific theories and assumptions related to astrophysics, environmentalism, nano-technology, computer architecture and higher-dimensional parallel universes. The following analysis contains spoilers.
The novel is divided into three sections.
- In "Part I: Silent Spring", a young astronomer named Ye Wenjie witnesses the killing of her father during the Chinese Cultural Revolution, after which she becomes conflicted about mankind's abuse of nature. Later, she is recruited into a secret radio-astronomy project.
- "Part II: Three Body" takes place in the modern day, where a rash of suicides among theoretical physicists prompts the government to recruit a nano-technology developer named Wang to infiltrate the secretive Frontiers of Science coalition (among whose members are the suicide victims). Wang is led to an online VR game named "Three Body", in which the player is confronted with an environment which alternates between "Chaotic Eras" and "Stable Eras". This situation is due to the fact that the planet is part of a triple-sun system. The Three Body Problem describes the seeming impossibility of predicting the flight path of objects interacting in a three-point gravitational system (such as a triple-sun system). It is eventually revealed that the Three Body game is a simulation of a real star system, Trisolaris (Alpha Centauri). The Trisolarans want to solve the Thre Body problem in order to predict the occurrences of recurring desert and ice ages (caused by the planet's varying proximity to one or more suns) so that they can better prepare for them. However, as no solution to the Three Body problem seems possible, they have decided to emigrate to a new planet.
- "Part III: Sunset For Humanity" describes the beginning of the conflict between Earth and the Trisolarans. Many disgruntled/disillusioned scientists and intellectuals (led by Ye Wenjie) ally themselves with the Trisolarans and welcome their invasion fleet (which will arrive on Earth in 450 years). However, there is division amongst the group as to the extent of their future control (or extermination) of humanity. In the end, the Trisolarans demonstrate their contempt for humanity's chances.
Part I: Silent Spring
- 1. The Madness Years: In 1967 China (during the beginning of the Cultural Revolution), Red Guard militants torture and kill intellectuals and frame science as tools of capitalism. A young woman named Ye Wenjie witnesses her physicist father being whipped to death.
- 2. Silent Spring: Two years later Ye Wenjie labors in the Greater Khingan Mountains. She reads Silent Spring, an English book about the effect of pesticides on the biosphere. She begins to think that mankind may need outside intervention in order to have a "moral awakening" with nature. She is soon arrested as an dangerous activist.
- 3. Red Coast I: Due to her background in astrophysics and her association with Yang Weining (one of her father's students), Ye is recruited into the secretive "Red Coast" project, located on Radar Peak, an area known by the locals for unexplained phenomena. There, she sees a giant radar dish lance out a beam of radiation at a mysterious target in the sky.
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| Subterranean Press, Marc Simonetti |
- 4. The Frontiers of Science: In the present day, a nano-tech developer named Wang Miao is brought to a secret military meeting where he is informed that members of a scientific think tank named the "Frontiers of Science" have been committing suicide upon some critical scientific discovery. The military commander, General Chang, convinces Wang to infiltrate the Frontiers of Science. Chang also implies that they have been waging a kind of "secret war" with them.
- 5. A Game of Pool: Wang visits Ding Yi, the fiance of Yang Dong, one of the suicide victims. Using a pool shot as an example, Ding demonstrates to Wang that particle acceleration experiments are producing random, unpredictable results, thus implying that the laws of physics are all false. This shocking realization had driven Yang Dong to suicide.
- 6. The Shooter and the Farmer: In the ensuing days, Wang begins to see a strange countdown in the corner of his eye. When he consults Shen Yufei, a member of the Frontiers of Science, she tells him to stop his nano-tech research. He does this and the countdown image disappears. He thinks of the "shooter/farmer" analogy, in which unexplained phenomena are the result of forces outside of mankind's perception. Nonetheless, Wang maintains that he is a victim of an "illusionist", and demands that Shen provide him concrete proof of the higher power she attributes these phenomena to. Shen tells Wang that in three days the universe will flicker.
- 7. Three Body: King Wen of Zhou and the Long Night: Wang returns home and logs in to "Three Body", a VR game website which he had seen Shen logged into at her house. In the game, he meets character avatars derived from ancient Chinese dynasties. After traveling to a gigantic pyramid ruled by King Zhou, he witnesses the world go through unpredictable heat waves and ice ages. In the end, the world freezes over and a prompt states that "Civilization Number 137 was destroyed by the extreme cold. This civilization had advanced to the Warring States Period before succumbing." As he departs the game, he sees three stars in the sky.
- 8. Ye Wenjie: Wang visits Yang Dong's mother, who turns out to be Ye Wenjie, now retired from a teaching career. She seems content with her life, but regrets having exposed her daughter to such deep scientific thoughts (leading to her suicide). She puts Wang in contact with some microwave radiation technicians so that Wang can confirm Shen's prediction.
- 9. The Universe Flickers: At the Miyun Radio Astronomy Observatory, Wang and the technician on duty are stunned to see the background microwave radiation level of the universe fluctuate. Wang notices that the wavelength fluctuations amount to Morse code values matching the continuing countdown he had seen before.
- 10. Da Shi: Afterwards, Wang runs into Da Shi, General Chang's brusque, ex-police enforcer. Shi states that he does not know what his superiors know, but suspects that some anti-technology agent (or agency) is creating "disturbances" (sabotage) among the scientific community in order to discourage further developments (or provoke them into suicide).
- 11. Three Body: Mozi and Fiery Flames: Wang reenters the Three Body VR game site and witnesses the Earth destroyed by fire from a gigantic sun. He believes that the game is hiding clues about what is happening in the real world. Afterwards, he visits Ye Wenjie, who offers to tell him about her time on the Red Coast project.
- 12. Red Coast II: In 1969 at the Red Coast Base, Ye Wenjie is told that the radar dish fires a beam of microwave radiation at foreign space targets in order to destroy them. However, as she rises in position, she learns that this is only a cover story.
- 13. Red Coast III: Declassified documents describe the true purpose of the Red Coast Base: to search for the possible existence of extraterrestrial intelligence and if found, attempt contact and exchange.
- 14. Red Coast IV: In the present, Ye tells Wang that their efforts at alien contact were unsuccessful, and as far as she knows, only Earth contains intelligent life. The Red Coast Base was ultimately decommissioned, after which Ye went into academia.
- 15. Three Body: Copernicus, Universal Football, and Tri-Solar Day: Back in the Three Body VR game, Wang finds himself in an environment modelled after the European High Middle Ages. He explains to some of the scientific leaders of that age that the unstable periods of heat and cold are apparently due to the fact that the planet is being passed around like a football in a 3-star (tri-solar) system. While in orbit around a single sun, the planet experiences a "Stable Era". When the planet is being passed between suns, a Chaotic Era occurs. The conference is destroyed in a blaze of fire (due to the appearance of all three suns in close proximity), but the game end message states the a second level has been reached.
- 16. The Three-Body Problem: Wang visits Da Shi's police headquarters where Wei Cheng (Shen Yufei's husband) describes how his intimate understanding of the Three Body problem (to define a formula to predict the movements of a planet in a tri-solar system) brought him into Shen's Frontiers of Science circle. One day, Wei had been ordered by some members of the Frontiers of Science to stop his Three Body problem research or he will die. However, Shen insisted that he continue. Da Shi decides to go to Shen's house to interrogate her. At Shen's house, they discover that she has been shot dead. Wei tells Da Shi that Shen had recently been arguing with her Frontiers of Science colleague, environmentalist Pan Han.
- 17. Three Body: Newton, Von Neumann, the First Emperor, and Tri-Solar Syzygy: When Wang next enters the Three Body VR world, he meets physicist Isaac Newton and computer theorist John von Neumann, and tells them that they should build a computer to predict the motion of the three suns. They approach Chinese emperor Qin Shi Huang, who allows them to use his army to create a "human computer system". Unfortunately, just as the computer's results are about to bear fruit, the three suns line up in a syzygy, causing everything on the planet to be sucked up into the nearest sun. After exiting the game, Wang is invited to a player get together by a game administrator.
- 18. Meet-up: The meeting is led by Pan Han, the prime suspect in Shen's murder. He tells the seven participants that the game is a simulation of a real world named Trisolaris (although the Trisolarans do not necessarily appear human). He asks the group how they would feel if the Trisolarans came to Earth. Five members welcome the effect they would have on mankind, feeling that this would improve man's morality. The other two (who are more wary of this idea) are dismissed.
- 19. Three Body: Einstein, the Pendulum Monument, and the Great Rip: On his next trip to Three Body, Einstein tells Wang that Newton's computer had failed because it had not included Einsteinian mathematics in its predictions. Even worse, there is no possible solution to the Three Body problem. Wang also learns that Trisolaris has broken up into two planets due to extreme gravitational forces, and will eventually be consumed by one of the suns. Thus, the Trisolarans have decided to seek out a new home.
- 20. Three Body: Expedition: When Wang next enters the game, he sees the Trisolaran Interstellar Fleet launch into outer space, its mission to reach a nearby star and investigate the possibilities of emigration.
- 21. Rebels of Earth: Later, Wang attends a full gathering of the ETO (Earth-Trisolaris Organization). The Commander of the ETO is revealed to be Ye Wenjie. She has Pan Han (an Adventist) executed for killing Shen without express orders. She then tells Wang that the Red Coast Project had never ended.
- 22. Red Coast V: In 1971 at the Red Coast base, Ye learns that a signal to space can be amplified if bounced off the sun, thus finally making it strong enough to reach extraterrestrials. Although politically forbidden, she surreptitious makes a test transmission.
- 23. Red Coast VI: Nine years later, while monitoring the dish receiving monitor, Ye detects a message from Alpha Centauri. The message is from a Trisolaran pacifist who warns Ye not to make further transmissions, otherwise the Earth will be detected and invaded. Disgusted with the Cultural Revolution and what mankind in general has done to her own planet, Ye sends out a transmission inviting the Trisolarans to come to Earth and take over. The next day she learns that she is pregnant.
- 24. Rebellion: Back in the present, Ye explains that the ETO want Wang to halt his nano-tech research in order to prevent the development of space elevators, which would allow mankind to build space defenses. At that moment, Da Shi's police forces attack the building, and after a brief standoff involving a nuclear bomb, the members of the ETO are all arrested.
- 25. The Deaths of Lei Zhicheng and Yang Weining: During an interrogation, Ye recounts how her superior Lei Zhicheng had found out about the response from the pacifistic Trisolaran (but had not yet known that she had replied). He tells her not to reply. The next day, she arranges for Lei's death in an accident. Unfortunately, she is forced to kill her husband Yang Weinig in the same incident.
- 26. No One Repents: As the Cultural Revolution winds down, Ye returns to the city and begins to think twice about her "betrayal of mankind". However, when she confronts the Red Guards who had killed her father, they do not repent. Ye's feelings about humanity's need for an outside invasion harden.
- 27. Evans: One day while helping a team search for a spot to build a radio astronomy observatory, Ye meets Mike Evans, a wealthy idealist who wants to save the endangered species of Earth. Later, when Evans expresses despondency over mankind's continued penchant for environmental destruction, Ye tells him about the Trisolarans and they form a partnership.
- 28. The Second Red Coast Base: Three years later, a secret helicopter brings Ye to a ship named Judgement Day. She learns that Evans has built this ship to be a second Red Coast. Evans informs her that the Trisolarans will arrive in 450 years, and makes her the Commander-in-Chief of the Earth-Trisolaris Movement.
- 29. The Earth-Trisolaris Movement: In the ensuing years, the ETO grows to large numbers, made up mostly of intellectuals. The Three Body game is developed as a recruitment tool for the lower classes. During this time, the world powers begin waging a "secret war" against the ETO. Also, three factions arise in the ETO: The Adventists (who simply want humanity destroyed), the Redemptionists (who want to save the Trisolarans by solving the Three Body problem), and the Survivors (who hope to capitulate to the Trisolarans and thus survive the invasion).
- 30. Two Protons: Ye tells her interrogator that the Adventists have messages from the Trisolarans from 4 years ago, after which all transmissions then stopped. As a Redemptionist, Ye would like to destroy the Adventists' HQ (Judgement Day), but cannot risk losing the final Trisolaran messages. She also states that the Trisolarans had successfully accelerated 2 protons to the speed of light so that they could hit the Earth. She hints that this act somehow puts a "lock" on the development of technology on Earth.
- 31. Operation Guzheng: The world's military gathers in order to formulate a plan to retrieve the data from Last Judgement before it can be erased by defeated Adventists. Using a plan devised by Da Shi, a web of nano-filament is stretched across the Panama Canal. When the Last Judgement passes through it, it is sliced to pieces, killing everyone on board but preserving the data.
- 32. Trisolaris: The Listener: 1975: On Trisolaris, a "listener" (one of thousands) receives Ye's Red Coast test transmission. Fearing that a Trisolaran emigration will result in mankind's extinction, he sends back a warning. When the Trisolaran Princeps (king) learns of these events, he exiles the listener and then has his fleet launch immediately, even though they do not have a precise fix on the message's point of origin.
- 33. Trisolaris: Sophon: Nine years later, the Trisolarans receive Ye's invitation answer. They then decide that for their invasion to be successful they must halt mankind's technological development, and the best way to do that is to have Earth agents emphasize the negative environmental effects of scientific development. Trisolaris must also convince humanity that studying physics is a futile waste of time. In order to accomplish this, the Trisolarans develop AI supercomputers which can be contained in protons (encased in higher dimensional space). Two of these super-computer protons - Sophons - are sent to Earth where they enter partical accelerators to create unaccountable test results (initiating the wave of physicist suicides). They can also create retinal images (causing Wang's "countdown" to appear). They can also blanket the Earth and vary their permeability in order to create "flickering" in the background microwave field. Finally, due to quantum entanglement, they can communicate with paired Sophons on Trisolaris in realtime in order to coordinate communications with the ETO. When General Chang tells the general assembly that they are now aware of the Sophons and the Trisolarans' plans, everyone suddenly receives a retinal image message stating "You're bugs!".
- 34. Bugs: Wang and Ding Yi fall into despondency, but Da Shi points out that even after thousands of years mankind has been unable to eliminate the problem of bugs on Earth. They cheer up.
- 35. The Ruins: Ye visits the desolate ruins of Red Coast and sees her last sunset, comparing it to the last sunset of humanity.
