During China's
Cultural Revolution, astrophysicist Ye Wenjie witnesses her father beaten to death during a
struggle session. A political outcast, Ye is initially sentenced to a labor camp but is then recruited to "Red Coast," a secret military initiative attempting to
search for and
communicate with extraterrestrial life. At Red Coast, Ye discovers a method to amplify
radio frequency transmissions using the Sun, with which she secretly broadcasts a message. Eight years later, she receives a reply from the alien planet Trisolaris, which warns her not to make any further communications to avoid the Trisolarans learning the location of Earth and subsequently invading. Disillusioned by humanity's inability to live harmoniously with itself and nature, Ye invites the Trisolarans to Earth to settle its problems. After China's
reforms, Ye encounters Mike Evans, heir to the world's largest oil company but also a radical environmentalist who shares Ye's ideals and disappointment in humanity. Ye discloses Trisolaris' existence to Evans, who founds and finances the secret Earth-Trisolaris Organization (ETO) as a militant
fifth column for Trisolaris, with Ye as the ETO's leader. Through Trisolaris-ETO communications, Trisolaris is revealed to be a planet orbiting the
ternary star system of
Alpha Centauri. Because of the
three-body problem, the three stars' movements (and Trisolaris' position relative to them) are
chaotic and unpredictable. As a result, Trisolaris experiences great climate extremes, alternating between temperate "Stable Eras" during which civilization thrives, and "Chaotic Eras" of climate catastrophes. The worst such catastrophes are civilization-ending. Hundreds of Trisolaran civilizations have risen and fallen, each attempting but failing to develop an accurate calendar that can predict and help prepare for Chaotic Eras. Upon reception of Ye's broadcasts, the current and technologically advanced Trisolaran civilization identifies Earth as a colonization target, which will permit the Trisolaran civilization to escape their inhospitable and ultimately-doomed home planet. It dispatches an invasion force on a 450-year journey to Earth. However, the Trisolaran leadership is concerned that Earth's accelerating technological developments will outmatch the invasion force by the time of its arrival. Therefore, Trisolaris develops "sophons" (minuscule supercomputers embedded in single
protons) in order to arrest Earth's technological development by interfering with its scientific experiments. By the late-2000s/early-2010s, the sophon-induced apparent breakdown of science on Earth has prompted the suicides of prominent scientists. This alarms Earth's governments, who form an international task force to investigate, recruiting
nanotechnologist Wang Miao and detective Shi Qiang. As part of his investigation, Wang plays the
virtual reality video game
Three Body, which is a simulation of Trisolaris created by the ETO to identify potential recruits and to garner sympathy for the Trisolaran plight. Wang's successes in
Three Body result in his induction into the ETO, where Ye reveals to Wang the full extent of the conspiracy. Wang also witnesses the schism between the "Adventist" faction of the ETO, which views humanity as irredeemable and promotes its complete destruction by Trisolaris, and the "Redemptionist" faction, which aims to save the Trisolaran civilization by developing a solution to the three-body problem and producing an accurate calendar. Tipped-off by Wang, Shi and the
People's Liberation Army raid the meeting, arresting Ye. An international military force then seizes the converted oil tanker housing ETO's communications with Trisolaris. From these actions, Earth's governments directly learn of Trisolaris' existence and the approaching invasion force. Wang and his colleagues resolve to fight in Humanity's defense. == English translation ==