During the 2035 trial run of the Star-Ring High-Speed Railway, an accident occurs. Seventeen-year-old ordinary high school student Lin Xiaoman is caught in a rift in time and space and falls into Xinjing City ten years in the future. Technology here is highly advanced, yet the city is overshadowed by the "Temporal Erosion Crisis": some people are gradually turning transparent and disappearing due to disruptions in space-time, while the legendary "Bullet Train Hero," guardian of time and space, has vanished without a trace.
While Xiaoman is lost and confused, she meets a girl who looks exactly like her, Su Mingxia. She is a "Temporal Observer" from the future, and what Lin Xiaoman will look like ten years from now. Su Mingxia tells her that the Star-Ring High-Speed Railway accident ten years ago was no accident, but a conspiracy targeting the balance of space-time. The only way to repair the rift is to find the "Temporal Track Keys" scattered across both timelines.
To return to her original world and prevent the future tragedy, Lin Xiaoman is forced to work with Su Mingxia. She gathers clues while hiding her identity at a modern-day school, and fights the villainous organization "Reverse Time Bureau," which is trying to control time, in the futuristic city. Along the way, she gradually unlocks her special gift of "innate temporal sensitivity" and uncovers the truth about the "Bullet Train Hero": it is actually a space-time guardian System that can bond with human consciousness. Her father was the developer of the first "Bullet Train Hero"...
As love (a mirror bond with her future self and a modern-day academic ace's secret crush), friendship (a best friend across time), and responsibility (saving two worlds) intertwine, Lin Xiaoman must choose: will she cling to her ordinary present, or become a hero burdened by destiny?
