About 8.6 Earth years after the warning message to Earth, the Trisolaran princeps calls an emergency meeting and reveals that Earth has replied. The response proves that Earth is only 40,000 light-hours away, the nearest star, so the fleet is redirected toward it. But the discovery immediately creates a new fear: after studying human history, the Trisolarans conclude that humanity’s scientific development accelerates rapidly, unlike their own. Because the voyage will take millions of Trisolaran hours and many ships may be lost en route, the princeps judges that the fleet could arrive only to face a stronger Earth civilization and provoke a future human counterattack on Trisolaris.

To avoid that outcome, the princeps argues that Trisolaris must not merely attack Earth later, but halt human science now. The consuls discuss using Earth’s internal traitors and apparent miracles to weaken scientific thinking, yet the princeps introduces a more decisive solution: Project Sophon, which aims to unfold a proton and turn it into a superintelligent computer. The first attempt fails by unfolding the proton into one dimension, creating immense but nearly massless glowing threads that drift through the atmosphere. The second attempt fails by unfolding the proton into three dimensions, producing huge reflective solids. Some reveal intelligence within the proton’s higher-dimensional microcosmos, merge into a giant eye, and then become a parabolic mirror that focuses sunlight onto the Trisolaran capital before space defenses destroy it.

Although the failed experiments are dangerous and the military consul warns that worse failures could create a black hole, the princeps accepts the risk and orders another attempt. The third unfolding succeeds: the proton becomes a two-dimensional plane that expands across the sky, reflects the opposite hemisphere, and is gradually bent by gravity into a shell around Trisolaris. This membrane blocks sunlight and drives the planet into lethal darkness and cold, forcing most of the population into dehydration storage while thousands of ships etch vast circuits onto the proton’s surface. After long construction and debugging, Sophon One comes online. It proves that it can change dimensionality, shrink or expand its projection into normal space, see inside bodies from higher dimensions, and enter sealed spaces without crossing them in ordinary three-dimensional ways.

Trisolaris then builds Sophon Two, Sophon Three, and Sophon Four, and links them through a quantum sensing formation so they can function even when reduced back to subatomic size. The science consul explains that Sophon One and Sophon Two will be sent to Earth at nearly light speed. There they will infiltrate particle accelerators, intercept high-energy collisions, and generate chaotic false results, preventing humans from learning the deep structure of matter and locking physics at its present level. Because sophons move so quickly, each can effectively interfere with thousands of accelerators at once. They can also support the Miracle Plan by writing messages on film or directly on human retinas and by making cosmic background radiation appear to flash, pushing science and culture toward superstition and confusion. Sophon Three and Sophon Four remain on Trisolaris so the two worlds can exchange information in real time through quantum links.

The chapter then shifts back to Earth, where the captured Trisolaran communications are being read and analyzed. Ye Wenjie reads the messages while, at the Battle Command Center, General Chang warns that sophons are probably already watching the meeting, meaning secrecy has effectively ended. Three seconds later, Trisolaris sends humanity its first direct communication outside the ETO and then cuts off further messages to the Adventists. The sentence appears in everyone’s eyes for an instant and states the Trisolaran view of humanity with brutal finality: "You’re bugs!"