Ye Wenjie regains consciousness in a helicopter, feverish and in pain after her imprisonment. Two PLA officers are with her: Political Commissar Lei Zhicheng and Red Coast Base chief engineer Yang Weining. They show Ye one of her old astrophysics papers and reveal that they have brought her because the base needs her specialized scientific knowledge.

While Ye rests, she overhears Lei and Yang arguing about whether taking her is appropriate. Yang explains that Red Coast needs someone with her expertise, but normal channels have failed because the work requires military status, high security clearance, and long-term sequestration at the base. Lei worries that using a convicted political prisoner is dangerously irregular, but Yang insists there is no better option and accepts responsibility for the technical risk.

During the flight, Ye recognizes Yang as one of her late father Ye Zhetai's former graduate students. She remembers Yang as talented but cautious, especially about avoiding politically dangerous theoretical work. This memory explains both their prior connection and Yang's careful behavior in front of Lei.

After landing at Radar Peak in the Greater Khingan Mountains, Ye is taken to the gate of Red Coast Base. Lei tells her that her counterrevolutionary crime is proven, but that she can redeem herself through labor at this defense research facility. Once they are alone, Yang speaks frankly: if Ye refuses, she will likely receive a prison term of several years, but if she enters Red Coast, the secrecy of the project may mean she never leaves. Ye immediately chooses to go in, preferring permanent isolation at the base to returning to the outside world.

Inside the base, Yang tells Ye the project is a large-scale weapons program whose success would surpass even the atomic and hydrogen bombs in importance. He brings her near the transmission main control room, where Ye waits outside and hears the operators begin Red Coast's one hundred and forty-seventh transmission. As the countdown ends, the antenna emits a powerful field that makes clouds glow blue; equipment briefly fails and backup systems engage, but the transmission continues.

Ye then witnesses the transmission's destructive power firsthand. Birds startled from the forest fly into the antenna's path and fall dead from the sky. After about fifteen minutes, the transmission ends, the base shifts into monitoring mode, and the forest gradually quiets again. Looking at the giant antenna under the cold 1969 night sky, Ye sees both the scale and the unsettling force of the secret project she has just joined.