On a rainy night, Mr. Chen of Chen's Watch Shop in the old town was stabbed to death with a watch repair knife in the shop. The warm Longjing at the scene and the signs of no break-in pointed to a crime committed by an acquaintance. The rusty gear with the word "Su" engraved on the palm of the deceased's hand is closely related to the watchmaker Su Zhenhai who disappeared thirty years ago, and his most precious enamel clock was missing.
As soon as Lin Yan, a criminal police officer who was transferred to the police station, took over his first case, he encountered the restorationist Lao Zhou who died in the same way. The old account books in the studio revealed the truth about Su Zhenhai's "selling a clock to save his wife". Su Zhenhai's daughter Su Wan appears with her father's last words that "there is truth in the clock", Mr. Chen's unusual familiarity with his apprentice Jiang Chen, the mysterious tombstone in the cemetery, Su Zhenhai who has disappeared for thirty years... Under layers of fog, there is a blood debt spanning three generations, and the obsession with life and death locked in the shadow of the enamel clock.
