Ling Shiyan is a piano tuner with one-ten thousandth pitch accuracy. Her ears can capture "historical sound marks" that ordinary people cannot perceive - the subtle sound marks left in the resonance of objects. The vibration of the piano keys records the emotional ups and downs of the player, and the friction of the door handle hides the user's unique information. When she was tuning a weathered second-hand Steinway grand piano, the sound of hammer hammers was mixed with distant and vague gunshots and desperate calls for help. This is not science fiction, but the real past revealed by Ling Shiyan's extraordinary hearing. She teamed up with Chang Jiang Lin, a rigorous and pragmatic criminal forensics officer, to establish an "object voiceprint database" to explore the boundaries of sound as physical evidence. With the metalwork remaining for three years and the woodwork for only six months, her abilities are by no means omnipotent. From the unique "whining" of a murder weapon's metal fatigue that identified serial killers to ultimately promoting the birth of the "Criminal Acoustic Evidence Collection Standards", Ling Shiyan used her ears that can hear the "heartbeat" of the world to not only tune the strings, but also calibrate a new dimension of forensic forensics, demonstrating the irreplaceable and unique value of piano tuners in court.
