Half a year after a joint session of the UN and the Solar System Fleet elected Cheng Xin as Luo Ji’s successor, Cheng Xin descends by high-speed elevator to the Deterrence Center in the Gobi Desert. As the layers of earth grow thicker above Cheng Xin, the responsibility of controlling the gravitational wave deterrence system weighs heavily on Cheng Xin.

The Deterrence Center lies about forty-five kilometers underground, beneath Earth’s crust and into the mantle. It is formally named Gravitational Wave Universal Broadcast System Control Station Zero and is built to survive extreme pressure and heat through independent air circulation and powerful cooling systems.

When Cheng Xin arrives, Cheng Xin finds a stark, empty lobby behind a black steel door marked with the insignias of the UN and the Solar System Fleet. The blank, unused-looking space reflects Luo Ji’s only design instruction from decades earlier: the center should be "as simple as a tomb."

Most of the handover ceremony has already taken place on the surface, where humanity’s leaders watched Cheng Xin enter the elevator. Only the PDC chair and the Solar System Fleet chief of staff accompany Cheng Xin for the final transfer of authority.

The PDC chair tells Cheng Xin that the interior can be redesigned to suit Cheng Xin’s wishes, with comforts such as plants, a lawn, a fountain, or holographic surface scenes. The chief of staff says they do not want Cheng Xin to live as Luo Ji did, but although Cheng Xin is warmed by the gesture, Cheng Xin’s burden remains unchanged.