After leaving Ye Wenjie’s home, Wang Miao remains deeply unsettled because Ye’s account of Red Coast seems to connect with the strange events surrounding Three Body. To steady himself, Wang logs into the game for a third time, now with a clear objective: solve the world’s mystery. He creates a new identity, Copernicus, and enters a version of Three Body modeled on medieval Europe.

Inside a vast Gothic pyramid, Wang meets a group of scholars and rulers identified as Pope Gregory, Aristotle, Galileo, and Leonardo da Vinci. They recognize him from earlier civilizations and invite him to present his theory. Wang explains that the world has three suns, not one, and that their shifting gravitational influence causes the alternating Stable Eras and Chaotic Eras; he compares the planet to a football kicked among the suns. He also argues that the distant suns often appear only as flying stars because of an optical effect involving the suns’ outer layers and the planet’s atmosphere.

The others attack Wang’s logic and reject his explanation as heresy. Galileo and Aristotle demand observational proof, while the pope quickly orders Wang to be burned. Leonardo alone shows some hesitation, considering old records and calculating quietly, but he does not stop the execution. When Wang threatens to return under another identity, Leonardo reveals that the system records retinal scans through the V-suit, which terrifies Wang because it suggests the game is tracking him more deeply than expected.

Just before the execution, a burning knight bursts into the hall and cries that the world has ended, ordering everyone to dehydrate. Wang escapes the stake and runs outside, where he sees the planet being consumed by heat and fire. Pope Gregory, Galileo, Aristotle, Leonardo, and the others burn as they gaze upward, and Wang finally sees three gigantic suns filling the sky: a tri-solar day. After the suns set and civilization 183 is annihilated, the game announces that Copernicus has correctly revealed the basic structure of the universe and that Three Body has advanced to its second level.