Taking the anti-drug policeman Guan Tianhang (played by Wang Qianyuan), an investigation of a drug unsolved case three years ago, the main line reveals the justice and evil battle between him and his childhood sweetheart Yuan Yuexin (played by Jiang Xin) due to opposition.Through the confrontation between the two strong and the confrontation between light and dark, the plot presents the process of the anti-drug police pursuing the truth under heavy pressure, and finally ends with Guan Tianhang bringing the real murderer to justice.