Death's End

During the fall of Constantinople, Helena, a self-proclaimed witch, comes to Constantine XI, claiming that she can go anywhere and retrieve anything undetected. To prove this, she kills a prisoner by extracting his brain; to do this, she goes to a secret minaret where she can perform magic. Constantine tasks her with bringing him the head of Sultan Mehmed II. She fails, and the city falls. When Constantine’s men find her, she claims the magic is gone, so they kill her.

Helena’s abilities actually came from a four-dimensional fragment that intersected with Earth for nearly a month. When it disappeared the day before the sultan’s final attack, Helena was left powerless.

Yang Dong walks through the particle accelerator she oversees. Her mother, Ye Wenjie, was the first person to make contact with the civilization of Trisolaris. Yang Dong contemplates the encrypted messages she recently found showing how her mother invited the aliens to save Earth by destroying humanity—her revenge for her family’s suffering during China’s Cultural Revolution. The Trisolarans live on a planet torn between the changing gravities of three suns, making it only habitable at certain times. This instability makes them eager to conquer the meteorologically stable Earth. The knowledge that alien life exists shakes Yang Dong’s perception of the universe, and she struggles to accept her mother’s lifelong deception. She asks another scientist if he believes in God, since life can only spawn in highly specific conditions. He points out with a computer model that while the Earth spawned life, that life has impacted the Earth as well: Without life, the Earth would lose its water and become a husk. Yang Dong wonders how much of what humanity believes to be natural is actually natural.

Aerospace engineer Yun Tianming has terminal cancer. In his hospice room, he reads the newspaper and realizes that the Trisolaran invasion is fading from the headlines. China has legalized euthanasia for terminally ill patients. That night, Yun Tianming dreams of drifting across mirrorlike water in an origami boat.

Days later, Yun Tianming gets a visit from Hu Wen, a former classmate who is now a soft drink magnate. Hu Wen built his fortune on an idea Yun Tianming had, so he now gives Yun Tianming 3 million yen as repayment. Yun Tianming remembers Cheng Xin, another classmate whom he has always loved. The money will not help his treatment, so Yun Tianming decides to use it to buy Cheng Xin a star through the Stars Our Destination Project.

The Trisolaran Crisis shakes the foundation of human civilization. For the first few years, humanity’s dual approach to the crisis is nonsensical. One response is selling stars through The Stars Our Destination Project to raise money for the UN, which is now a world government. The second is to foster Escapism, or the idea that humanity can flee the Trisolarans by going to another star system.

Yun Tianming is the first person in China to buy a star. He buys DX3906, a star with no planets that is 286.5 light years away, and anonymously gives it to Cheng Xin. When the day of Yun Tianming’s euthanasia arrives, he must declare that he wants to end his life on a five times to ensure he is aware of the consequences. As he makes the declarations, he remembers his difficulty forging relationships. Despite this, he found a kind soul in Cheng Xin, who talked to him when other college classmates would not. While she went on to a graduate program, Yun Tianming’s professional life was lackluster, and he struggled to advance or make friends. When he was diagnosed with cancer, he tried to contact Cheng Xin, but could not find her.

At the last second, the euthanasia machine is unplugged. Cheng Xin enters, crying, and tells him that his aerospace background, illness, and desire to die make him a perfect candidate for the Staircase Project. This project is the work of the Planetary Defense Committee’s (PDC) intelligence arm. The idea is to send a human brain in a probe toward the Trisolaran Fleet; hopefully, including a person will interest the Trisolarans enough not to destroy the probe. Wade’s plan is for Yun Tianming to learn Trisolaran technology and spy on them.

The Trisolaran Crisis has led Cheng Xin to join the Technology Planning Center for the PDC’s Intelligence Agency, or PIA. Her direct supervisor is Mikhail Vadimov, a man well versed in both technology and espionage. She also works for PIA Chief Thomas Wade, a stern and calculating man who often takes pleasure in others’ discomfort.

At their first meeting, Wade announced that the PIA would launch a spy probe at the Trisolaran fleet at 1% of light-speed. The proposal is met with incredulity by scientists, who believe that the launch is impossible given the fact that technological advancement has been halted by sophons—multidimensional subatomic computers the Trisolarans have sent to spy and disrupt the study of physics. Cheng Xin proposes a super-lightweight probe pulled by a sail propelled by precisely positioned nuclear detonations. One problem is the probe’s limited capacity to actually spy on the fleet—the probe and the Trisolarans will be traveling at speeds that will make contact between the two last only a fraction of second. Wade instead suggests sending a human with the probe, incentivizing the Trisolarans to capture it. The PIA names this project the Staircase Program.

Before the Trisolaran Crisis, people believed that progress was inevitable and saw artificial hibernation as a way to reach better times. When the Trisolaran Crisis begins, governments suppress the technology, seeing it as a hopeless form of escapism in a doomed world. As fear of the invasion wanes, and hope for a better tomorrow returns, research into hibernation spikes.

The PIA realizes that if they are to send someone in the probe, the subject must be preserved through hibernation; however, hibernation technology is too heavy for the probe. Wade refuses to drop the idea, however, and instead suggests they merely send a brain.

Meanwhile, the PDC publicly announces the creation of the Wallfacers, a small group of men given almost unlimited resources and meant to strategize against the Trisolarans only in their minds. While sophons can see everything in the physical world and hack any technology, thoughts are still protected from sophon surveillance. Soon after the announcement, one of the Wallfacers, an heretofore unknown scientist named Luo Ji, is shot.

The Staircase Program represents an instance of technology being used in a way that transcends its era’s limits. By using a lightweight sail, strong but super thin cables, and a small capsule, the PIA is able to achieve 1% the speed of light, thought to be impossible with current resources and state of scientific discovery.

The PIA painstakingly searches for someone well-versed in aerospace science, near death, and willing to donate their brain. Three PDC nations legalize euthanasia for terminally ill patients in an effort to advance the search. Cheng Xin and Vadimov watch as the bombs meant to propel the probe are launched into space.

Cheng Xin loves the star she’s been gifted and wonders who her anonymous admirer might be. Hu Wen visits Cheng Xin and tells her about Yun Tianming’s illness. She suggests to the PIA that Yun Tianming could be a candidate.

In the hospice room, Cheng Xin asks Yun Tianming to be the person they send to the Trisolarans. He does not want to go, worrying the Trisolarans may study his brain and simulate pain and torture. However, his love for her triumphs and he agrees.

Cheng Xin remembers meeting Yun Tianming in college; she felt that she needed to protect him. She regrets suggesting him as a candidate for the probe, but when she tells Wade that Yun Tianming is unsuitable because of his isolation, Wade argues that the loneliness is actually an advantage. Yun Tianming is asked to pledge his loyalty to humanity at the UN, but he refuses, saying he has no love for humanity. This is actually the final test, which should show the Trisolarans that Yun Tianming could potentially be useful to them.

Cheng Xin wants to see Yun Tianming before he dies, but she rushes to the hospital too late: The operation to remove his brain is complete. The next day, Cheng Xin tells Wade to include some seeds in Yun Tianming’s capsule, hoping that in some distant future, wherever he ends up, he can plant them to feed himself.

Wade asks Cheng Xin to hibernate so that someone who knows Yun Tianming will be present for his capture years in the future. She agrees. However, during launch, an accident throws off the probe’s trajectory. Despite this, Cheng Xin still hibernates, wanting to be lost in time like Yun Tianming is lost in space.