Wang goes to Ye to learn more about Red Coast. Ye tells him about her experience of being selected as a member of the base.

Yang tries his best to keep Ye away from the core of Red Coast. Lei personally engages Ye for unknown reasons.

Shi and Wang encounter a murder investigation on their train journey to Hailar, realizing Shen is targeted by another formidable force. Ye advises Shen's safety while sharing her past with Wang.

Transferred to a secret department, Ye learns the truth about Red Coast with Yang's help. Despite the disappointment, she stays, driven by the pursuit of extraterrestrial life, bidding farewell to Wang.

Wang receives an invite to the ETO meeting. Clues reveal Chen as an ETO member. Wang prepares for the meeting, knowing it implicates Ye.

Ye proposes using the sun to send signals into space, facing opposition. Despite risks, she conducts the experiment secretly. Years later, she receives three ominous messages from space.

Ye learns of Trisolaris and decides humanity's fate. She reveals the significance of Wang's research. Shi takes action against Chen, averting disaster.

Ye learns of her pregnancy just before Lei's attempt to monopolize the Trisolarian message.