Worldview structure: The story takes place in a northern heavy industrial city called "Crane City". On the surface, it is a hard fortress made of steel and coal, but underground there are huge underground cavities formed due to over-exploitation a hundred years ago. There is an unofficial agency called the "Shen Jing Bureau" in the city, which specializes in handling cases that are characterized by the police as "accidents" or "disappearances" but actually involve underground anomalies.
Core suspense: The protagonist Lin Xun is a "sound restorer" who specializes in repairing old audio tapes. While repairing a blank tape from the 1980s, he accidentally extracted a cry for help that was not of this world. As the restoration work progressed, he discovered that the tape was a "living container". Every time a section was repaired, a bizarre death would occur in reality that was synchronized with the contents of the tape.
Thriller mechanism: This book focuses on "auditory horror" and "psychological thriller". Horror does not rely solely on visual gore, but stems from the dislocation of sounds - such as the ever-increasing footsteps in the corridor late at night, tomorrow's news broadcast on the old radio, and the gradually clear memories in the protagonist's mind that are not his own.
Protagonist: Lin Xun, 28 years old, suffers from severe hyperacusis and is extremely sensitive to sound. He wears noise-cancelling headphones all year round. He has a withdrawn and indifferent personality, but in fact he has strong logical reasoning ability and a terrifying memory for sound details. He repaired the tapes not only for money, but also to find his sister who disappeared in the underground air-raid shelter ten years ago.
