In 2082, Beijing is folded into three layers of space. The 50 million impoverished residents of the Third Space have only four hours a day to survive. Lin Mo works as a “time miner.” After witnessing the brutal reality of a coworker dropping dead when his time runs out, he accidentally discovers a metal plate engraved with ancient code. It triggers a malfunction in the spatial-folding System, letting him glimpse the First Space, where people enjoy unlimited time. To treat his sick younger sister, he sneaks into a black market in the Second Space and meets the smuggler Su Li. Drawn into a time-theft operation, he acquires crucial data and exposes a loophole in the Time Bank's “time return” system.
As his investigation deepens, Lin Mo joins the resistance group “Reversers” and learns that the folding System runs on the “Time Sand Engine,” which extracts the life spans of the lower classes. The upper classes achieve immortality by upholding the “conservation of total time.” The team infiltrates the First Space and discovers that the wealthy use time to create an elixir of immortality, with their timers synchronized to the countdowns of the lower-class residents' lives. The Time Administration launches the “Mobius Protocol” to intensify the exploitation, trapping Lin Mo in a twenty-four-hour death loop. He escapes with Su Li's prohibited device.
In the final battle, the Reversers break into the heart of the Time Sand Engine and discover that it is actually a giant hadron collider. A hologram of the scientist Chu He reveals the “time entropy reduction” plan: reset everyone's remaining life span to twenty-five years, but only if a volunteer sacrifices all of their time. Su Li volunteers to become the vessel and restarts the global time network, causing the folded spaces to gradually come apart. Ten years later, Lin Mo has become a historian. He mourns the dead before a memorial, while an underground laboratory continues researching “Time Folding 2.0.”
