The evidence of the murder ten years ago reappeared, and the silver buttons connected a series of murders spanning ten years. Female forensic doctor Su Wan relied on her keen professional insight, and criminal police officer Chen Rui relied on her tenacious investigative will. Through cooperation and collision, the two gradually approached a deliberately buried chemical plant to reveal the truth. However, the real murderer used ten years of blood to draw symbols and used buttons to lay out a ritual killing... When the last button falls, can they uncover the redemption behind the blood?
