Reading the captured Trisolaran messages, Ye Wenjie imagines the beings behind them. The account shifts to Trisolaris, where Listening Post 1379 is one of thousands of lonely stations searching for intelligent life. During a Chaotic Era night, the post's aging listener notices that a received waveform is different from ordinary cosmic noise. A computer rates it Red 10, meaning it almost certainly carries intelligent information and even contains a self-interpreting code. The listener becomes the first Trisolaran to read a message from Earth, a peaceful greeting from a world with one sun and a stable climate.

After the transmission ends, the listener is overwhelmed by the beauty of the world he has just learned about. He imagines Earth's oceans, forests, and mild sunlight, then dreams of that paradise being destroyed by a Trisolaran fleet. When he wakes, his thoughts turn to his own life: he is old, low-status, isolated, and likely to become useless once contact is confirmed and old listening posts are reduced. Trisolaran society gives little value to individuals who cannot work, so he sees no future for himself. Because he cannot bear to lose Earth, even as an ideal, he decides to act.

The listener realizes that if Trisolaris can get Earth to reply, the round-trip time will reveal Earth's distance and make invasion possible. Concluding that the government will try to lure a response, he quickly composes his own message first, translates it into Earth's language, aims the antenna, and transmits a warning: Do not answer! Do not answer!! Do not answer!!! His personal desperation and moral revulsion toward Trisolaran conquest lead him to risk everything to give Earth a chance to remain hidden.

Five Trisolaran hours later, the princeps learns both of Earth's contact and of the unauthorized warning. In a calm interrogation, the listener admits what he did and explains that Trisolaran civilization is spiritually barren: survival overrides individuality, useless people are destroyed, authoritarian rule is absolute, and beauty, love, literature, and art are suppressed as weaknesses. The princeps agrees that Earth cannot be shared, both because Trisolaris needs living space and because humans are dangerous and would learn Trisolaran technology. Rather than execute the listener immediately, the princeps spares him so he can live long enough to see Earth's hope fail.

Afterward, the princeps punishes the wider monitoring bureaucracy, ordering thousands deemed responsible to be dehydrated and burned. A consul suggests sending a deceptive message to Earth, but the princeps refuses, fearing it could worsen the damage; he can only hope Earth ignores or misunderstands the warning. He then summons the fleet commander and orders that, once construction is complete, the first wave of the Trisolaran fleet should depart toward the source's rough direction. Even though the target's distance and exact coordinates remain unknown and the mission is extremely risky, the princeps decides Trisolaris has no other choice in the face of its dying, unstable world.