Collection of science fiction stories by Hao Jingfang who won the 2016 Hugo Award for Best Novelette for Folding Beijing which is included in this title. In the future, as per a cycle of 48 hours, Beijing is divided into 3 spaces. The first space has 24 hours, the second space has 16 hours, and the third space have 8 hours. In order to pool money to send his adopted daughter to kindergarten, Lao Dao, a garbageman in the third space, risks being entrusted by Qin Tian, a graduate student from the second space, to deliver a letter to his girlfriend in the first space. A story of 48 hours shows the three different worlds in a third-class citizen's eyes.