The Three-Body Problem

During the Cultural Revolution, astrophysicist Ye Wenjie watches her father Ye Zhetai die after a struggle session and later works in the Greater Khingan Mountains, where environmental destruction and Rachel Carson's Silent Spring contribute to her conclusion that humanity may need intervention from an outside force. After political persecution brings her to the classified Red Coast Base, Ye learns that its real purpose is to search for and contact extraterrestrial intelligence. She discovers that the sun can amplify a sufficiently powerful radio transmission and secretly sends a message into interstellar space. Years later, Red Coast receives a reply from a pacifist on Trisolaris warning Earth not to answer because a response would reveal Earth's location and invite invasion. Ye conceals the warning and sends a second message through the sun inviting Trisolaris to come to Earth. When Commissar Lei Zhicheng discovers the incoming signal, Ye sabotages a receiver repair and cuts the rope supporting Lei and her husband Yang Weining, killing both men to protect the secret.

Decades later, nanotechnologist Wang Miao is drawn into an investigation after a series of elite physicists die by suicide and particle accelerators begin producing inconsistent results. A countdown appears first in photographs he takes and then directly in his vision, stopping only after he halts work on the ultrastrong nanomaterial Flying Blade. Shen Yufei directs him to observe the cosmic microwave background, which appears to flicker in the same countdown pattern. Wang also enters the Three Body game, where repeated civilizations try and fail to predict the motion of three suns around Trisolaris. He eventually learns that the game represents a real civilization whose planet is repeatedly destroyed by chaotic stellar motion and whose long-term solution is interstellar migration.

Wang's investigation leads him into the Earth-Trisolaris Organization, which Ye commands after revealing Red Coast's history to environmentalist Mike Evans. The movement divides into competing factions. Adventists reject humanity and want Trisolaris to destroy it, Redemptionists worship Trisolaris and seek to save it, and Survivors hope cooperation will protect their descendants. Evans and the Adventists monopolize communications with Trisolaris aboard the ship Judgment Day. After soldiers raid an ETO gathering and arrest Ye and more than two hundred members, humanity still needs the intercepted messages stored on the ship. Shi Qiang proposes Operation Guzheng, which uses Wang's Flying Blade nanofilaments across the Panama Canal to slice Judgment Day into layers before its crew can erase the data. Investigators recover roughly twenty-eight gigabytes of Trisolaran messages from the wreckage.

Those records explain the crisis. A listener on Trisolaris received Earth's first transmission and sent the warning not to answer, but Ye's reply later fixed Earth's distance at forty thousand light-hours. Trisolaris directs its fleet toward Earth, yet its leaders fear that humanity's accelerating scientific progress will surpass their own technology during the centuries-long voyage. Project Sophon is therefore created to freeze Earth's basic science. Trisolaris unfolds protons into macroscopic dimensions, etches them into intelligent computers, and sends Sophon One and Sophon Two to Earth. Moving near light speed, they can corrupt high-energy accelerator experiments, create apparent miracles such as countdowns and cosmic-background fluctuations, and support continuous surveillance, while two linked sophons remain on Trisolaris for instantaneous communication. At the Battle Command Center, humanity receives a direct Trisolaran message: "You're bugs!"

Wang Miao and Ding Yi initially conclude that the sophon blockade makes long-term scientific defeat unavoidable, but Shi Qiang takes them to a locust-infested field and asks whether the technological gap between humans and Trisolarans is greater than the gap between humans and locusts. Humanity has never succeeded in eliminating bugs despite that advantage, and Wang and Ding return to their work. Ye, after learning the full nature of Trisolaran civilization, asks to revisit Red Coast. She climbs Radar Peak with a group of visitors but without accepting assistance, finds the rusted base of the old transmission antenna, and walks to the cliff where Lei and Yang died. As her strength fails, she watches the sun set over the clouds and calls it both her sunset and humanity's.