While the IDC all but gives up hope in deciphering further meaning from the fairy tales, Cheng Xin and AA make a breakthrough after seeing an origami boat driven by a small piece of soap: curvature propulsion, the means of accelerating a ship to lightspeed by “folding” space and pulling it ahead.
Newly inspired, the IDC gets back to work and the next chance discovery is the meaning of He'ershingenmosiken. It is thought to be a combination of places in Norway, the mountain Helseggen and island Mosken. They travel there and investigate a maelstrom that was written about centuries ago by Edgar Allen Poe. They theorize the almost inescapable nature of the maelstrom once you’ve crossed the threshold is meant to represent a black hole. This is coupled with the idea that the constant speed needed for the umbrella to work is supposed to represent the speed of light to come up with the idea for the Black Domain Project.
The Black Domain project would present a cosmic safety notice by enveloping the solar system in a reduced lightspeed black hole. This would present the solar system as non-dangerous since it could not be observed, however, others including Cheng Xin and AA consider it to be a prison from which humanity could never escape.
The other plan to be put under consideration is the development of lightspeed ships given the realization of curvature propulsion, but this plan quickly loses favor due to 2 major events:
The first incident is a false alarm that is triggered to alert the population of an incoming dark forest strike. Humanity is sent into wide-scale panic and those who have the means, without regard for the safety of others, launch their personal spacecrafts into space, killing thousands.
The second incident is what triggered the false alarm, the fact that trails are left from ships that utilize curvature propulsion, broadcasting the danger of the civilization even more.
The last plan is the continuation of the bunker project, a plan to develop large cities in space that would be shielded from the explosion of the sun. At a scale test of the bunker project, Cheng Xin encounters Thomas Wade once again. He urges her to give him control of her company to develop lightspeed ships, a task that Cheng Xin would not have the temperament to complete, given that it is banned. After consideration, she agrees under the condition that she has the option to re-assume control if there is any threat to humanity. Wade reluctantly agrees and Cheng Xin and AA enter hibernation.
60 years later Cheng Xin is awoken from hibernation by Cao Bin, a former swordholder candidate. Upon awakening she is astonished to realize she is aboard an enormous cylindrical space city. Cao Bin takes her on a tour of other cities in the area ranging from metropolitan, to extremely poor, and even an abandoned city that is built around a manufactured black hole.
She finally arrives at the space city run by her company and finds it under blockade. She meets back up with Wade to see a small-scale working experiment of curvature propulsion. Given the fact that the technology is outlawed, Wade has assembled a militarized force equipped with anti-matter bullets, capable of destroying a space city. Cheng Xin is horrified by the development and is almost surprised when Wade keeps his promise to her and hands control back over to her as she shuts it down and disarms the soldiers.
Wade is tried, convinced, and executed for crimes against humanity while Cheng Xin and AA take their ship, Halo to Jupiter and decide to re-enter hibernation once more until such time that the dark forest strike hits the sun so they are able to see humanity hopefully prosper and live in happiness in the era after sun has been destroyed and humanity emerges from its bunkers.