Death's End

62 years later, Cheng Xin and AA awaken in Bunker World, roused from hibernation because Thomas Wade wants to meet with Cheng Xin. In these space cities humanity has regressed and become less dependent on technology. Cheng Xin is in a city behind Jupiter—just as she had been during the Bunker World simulation. Cao Bin, a scientist from her own time who works with Wade, gives her a tour of the city; there is architecture similar to that of her own time, and she finds joy in hearing the conversations of people commuting from work. This new world, despite being so far from Earth, feels like home. Cheng Xin and Cao Bin spend a few days exploring other Bunker World cities, all but one of which are hidden behind planets, ready for a dark forest strike.

Cao Bin and Cheng Xin visit Lightspeed II, an abandoned ghost city that was a Black Domain Plan research facility that created a microscopic, stable black hole and injected it into Leda, a moon of Jupiter. However, the head scientist, Gao Way, was obsessed with the black hole; six years after research commenced, he breached safety barriers, floated too close to the black hole, and fell in.