Modern cities appear normal on the surface, but in fact there is a "law of destiny" - everyone's destiny is pulled by the "source track" like a star map, and major choices will trigger "track changes" and produce chain cause and effect. A few people are born with the ability to "observe the trajectory" (vaguely perceive the trajectory of destiny), and a very small number of "track-executors" can actively correct the trajectory of others through special media (such as bronze compasses, blood contract tokens), but they must bear "track punishment" (their own destiny is partially tampered with). Twenty years ago, a "source track collapse" incident led to the emergence of "trackless places" (areas of chaotic destiny) in many places around the world, becoming the focus of competition for black market forces and mysterious organizations.
