In the future city "Xinhai City" completely wrapped in steel and concrete, Lin Zhou, a history graduate, has a secret talent - he can "read" the emotional memories attached to old objects and spaces, and is a reclusive "urban echo engineer". When he was immersed in the poignant love of a tram driver a hundred years ago, he accidentally came across a shocking murder that was covered up by top dignitaries from that echo. This dangerous "echo" was like a thunder, making him the top hunting target of the mysterious organization "Eternal Group". In this cold city made of steel and data, Lin Zhou must shuttle between pursuits and use those "voices" from the past to piece together the carefully buried truth. What he protects is not only his own life, but also the soul of this city that will not be forgotten.
