Note: This summary is written according to the order of the novel’s action on Earth, rather than according to the novel’s structure, which isn’t always in chronological order. The Summary and Analysis sections proceed according to the novel’s structure. Following the lead of The Three-Body Problem, names in this study guide will be written with surname first. The protagonist Wang Miao's family name is Wang, and his given name is Miao.
The Three-Body Problem begins in 1967 in Beijing, China, during the Cultural Revolution. Ye Wenjie, one of the central characters of the novel, watches her father die during a struggle session at Tsinghua University. This event, combined with her treatment as a political outsider over the next few years, radicalizes Ye Wenjie, who grows to believe that it’s impossible for humanity to save itself—an outside force is required to redeem it. She is taken to the mysterious, remote Red Coast Base, where this belief (plus her access to technology and her knowledge of astrophysics) eventually leads to her contacting an alien race, the Trisolarans. She encourages them to conquer Earth. She kills her husband and her boss to keep her contact with the Trisolarans a secret, and she gives birth to a daughter, Yang Dong, who becomes a theoretical physicist.
Ye Wenjie’s position in society is eventually restored, and she leaves the Red Coast Base, though she never fully forgives humanity. She meets Mike Evans, an extremely wealthy Westerner who has similarly lost faith in humanity. She shares her knowledge of the upcoming alien invasion, and they form the Earth-Trisolaris Organization (ETO) to prepare for further Trisolaran contact.
Sometime around 2010, a series of mysterious incidents surrounds a nanomaterials researcher named Wang Miao, the main protagonist of the novel. He is contacted by the enigmatic Battle Command Center, where he’s badgered by Shi Qiang, a rude but effective police captain. He learns that many scientists have killed themselves, saying that physics is a lie (including Ye Wenjie’s daughter, Yang Dong). He begins seeing a mysterious countdown in his photographs, and then in his own vision. All of these incidents are revealed to be connected to the Frontiers of Science, a group of scientists/academics/theorists, and then, on a deeper level, to the still-secret ETO. The countdown only ends when Wang Miao pauses his scientific research. He, along with Shi Qiang and the rest of the Battle Command Center, become dedicated to solving the mystery of these events.
Through the Frontiers of Science, Wang Miao begins playing the video game Three Body, an immersive VR game designed by the ETO to recruit people to understand the Trisolaran plight: Their planet is in a system with three suns, which will soon lead to the destruction of their planet and species. As such, they’re looking for a new home—and Earth is perfect. The reality of the countdown, and extraterrestrial power more broadly, is proven to Wang Miao when the cosmic microwave background of the universe flickers just for him. The proof of Trisolaris’s influence causes Wang Miao to have a breakdown, but he’s comforted by Shi Qiang, who encourages him to buckle down and try to save humanity.
Decades after its foundation, the ETO has fractured into three factions: Adventists, Redemptionists, and Survivors. Ye Wenjie is the ETO’s commander-in-chief, or spiritual leader. She's arrested, and as she and others are questioned by the Battle Command Center, it is revealed that Mike Evans has been in secret communication with Trisolaris. The records of these communications are kept on his ship, Judgment Day, and even Ye Wenjie doesn’t know their contents.
Using Shi Qiang’s unconventional thinking and Wang Miao’s nanomaterials, the Battle Command Center destroys the Judgment Day and retrieves the files, which reveal many things: (1) Trisolaran culture is harsh, and not as morally advanced as Ye Wenjie believes; (2) Trisolaran invasion will happen in around 450 years; and (3) the Trisolarans have been using "sophons," extremely advanced and capable particles, to interrupt Earth’s scientific progress for years—essentially halting research so that Earth can’t develop the technology to fight Trisolaris when they invade centuries from now. These sophons inspired Yang Dong and the other scientists to kill themselves, and they’re responsible for Wang Miao’s mysterious countdown.
The Trisolarans, unfazed by being exposed, reveal their presence to the Battle Command Center, calling the people there “bugs.” Wang Miao is once again shaken at the threat of humanity’s extermination, but he and Shi Qiang rally—after all, for all of humanity’s advancement, they’ve never succeeded in eradicating bugs. Ye Wenjie, now an elderly woman, climbs to the old location of the Red Coast Base, where she first contacted the Trisolarans. Her vision goes black as she watches the sunset, saying, “My sunset. And a sunset for humanity.”
