Anti-narcotics officer Yi Yongzheng is sent back to his hometown to investigate a new drug case, only to discover that the drug cartel is closely tied to his old friend, Ding Zhitong, stirring up memories he thought he'd buried. Years ago, Ding had joined the cartel, led by "Third Master," in a desperate bid to earn money for her son's medical treatment. She soon became a key player, bringing in foreign drugs and thriving in the underground world. But in this ruthless, profit-driven business, loyalty runs thin, and betrayal is always close. Ding finds herself isolated and betrayed, even losing her husband in the process. In a moment of reckoning, she decides to turn over evidence of the cartel to Yi. However, her plan is uncovered by Third Master, sparking a deadly clash. Teaming up with Yi, Ding helps bring down the cartel, but must face the law herself.