The criminal police headed by He Bu Ke of Jingcheng Public Security Bureau have been investigating the drug trafficking case of Yuecheng gang. Due to insufficient evidence, they have been unable to start. One day, He Bu Ke happened to meet Yuecheng suspected of murder and took him back to the police station. The murderer killed Luo Xiaolan in order to take back a priceless diamond necklace engraved with the password of all the criminal evidence and financial situation of Yuecheng Group. After Luo Xiaolan's death, only Luo Xiaomei knew where the necklace was hidden. The police hope to prosecute Yuecheng for intentional homicide, and then find evidence of his drug trafficking and other cases, and wipe out his drug trafficking organization. For her own greed, Luo Xiaomei did not cooperate with the police at first, which brought the case investigation to a stalemate. . . .