The Cultural Revolution raged on, and astronomer WenjieYe experienced numerous hardships during this period. She was brought into the top-secret military project called the 'Red Coast Project.' Using the sun as an antenna, Ye Wenjie sent out the first signal of Earth's civilization into the universe, achieving a groundbreaking advancement in the search for extraterrestrial civilizations. Under the dominion of three irregularly orbiting suns, the 'Trisolaran civilization,' located four light-years away, underwent destruction and rebirth over a hundred times. They were forced to flee their home planet and, coincidentally, received a message from Earth. Filled with despair towards human nature, Wenjie Ye revealed Earth's coordinates to the Trisolarans, completely changing the fate of humanity.

Basic science on Earth was disrupted abnormally. Nanoscientist Miao Wang entered a mysterious online game called 'Three-Body' and began gradually uncovering the truth of this world. During a gathering of players, Miao Wang came into contact with a secret organization formed on Earth to deal with the arrival of the Trisolarans (ETO). The Earth Defense Organization's Chinese Combat Command, through the 'Guqin Project,' partially thwarted the schemes of the Redemptionists and the Arrivalists, who sought to disrupt human scientific and intellectual communities. It was revealed that the Trisolarans, trapped in a dire situation, had decided to invade Earth to find a stable environment for survival.

After disabling Earth's foundational science using advanced technology, the colossal Trisolaran fleet began its advance toward Earth, signaling humanity's impending doomsday.