Episode Summary
The episode uncovers the truth behind Yun Anna's murder from a year ago, revealing that Zhou Shaoxiong was the mastermind who framed his rival, Yang Libing. This revelation, pushed by investigator Lin Qiangfeng, causes a fatal rift in the syndicate, leading to the suicide of a key subordinate, Mo Kang. Meanwhile, the chemist Lu Shaohua, after being publicly humiliated by Zhou Shaoxiong, forms an alliance with Ma Yingzi, who reveals she is Yang Libing's widow, setting them on a shared path of vengeance.

Spoiler Alert
The Narcotic Operation Episode 25: Unraveling a Year-Old Murder
The episode throws us back one year to the tragic death of Zhou Shaoxiong's pregnant wife, Yun Anna. She was gunned down in the street, and her father, the syndicate head Yun Ding'en, immediately suspected his rival, Yang Libing. He tasked Zhou Shaoxiong with eliminating Yang Libing and his entire clan. Shortly after this bloody revenge, Yun Ding'en handed over control of the organization to Zhou Shaoxiong and retired.
In the present, the syndicate's business model is shifting. Yun Ding'en, who built his empire on heroin and strictly forbade methamphetamine, now supports Zhou Shaoxiong's venture into meth production. This is a major change from the past, where he had Mo Kang cut down a rival's prayer tree as a warning for dealing in meth. However, Yun Ding'en insists they don't abandon their lucrative poppy plantations and heroin trade, a condition Zhou Shaoxiong readily agrees to.
Meanwhile, investigator Lin Qiangfeng has always been suspicious about Yun Anna's death, believing Zhou Shaoxiong was the true culprit. Lacking evidence, he seeks out a local Wanbei police officer named Mindan. Mindan is initially terrified to speak. He reveals his father, a former magazine editor, was kidnapped and turned into a drug addict by traffickers as punishment for an article he wrote, a trauma that forces Mindan to keep his own father locked in a large iron cage. After Lin Qiangfeng's persistent waiting, Mindan finally shares what he knows about the case. The killer was a man named Nai Qin, a disabled ex-cop who worked for Yang Libing. A crucial detail emerges: Yun Anna's necklace was missing from the crime scene.
We then see the chemists, Lu Shaohua, Wang Lin, and Qiu Laibao, living in a gilded cage. They are confined to their lab and residence, under 24-hour armed guard, with piles of cash they can't spend. Lu Shaohua is also being monitored by Ma Yingzi, who was sent by Zhou Shaoxiong. He quickly sees through her lies and confronts her, forcing her to admit she is his spy.
Lin Qiangfeng attempts to break the syndicate from within by turning Zhou Shaoxiong and Yun Ding'en against each other. He asks Gu Feng, an old acquaintance of Yun Ding'en, to make a call and plant seeds of doubt about Yun Anna's murder. Gu Feng refuses, fearing for his family's safety.
After Lu Shaohua successfully completes a massive meth order, which Zhou Shaoxiong proudly names "King Kong Drill," he asks for permission to return home to handle personal matters. Zhou Shaoxiong angrily refuses and, at a celebratory meeting, publicly humiliates Lu Shaohua by calling him his "dog" in the local Wanbei dialect. Lu Shaohua doesn't understand, but Ma Yingzi does and defends his honor by downing a large glass of alcohol for him.
Later, a drunk Ma Yingzi tells Lu Shaohua about the insult, solidifying his resolve to stand against Zhou Shaoxiong. He carries her back to her room, where she seduces him, and the two become intimate.
The tide turns when Gu Feng has a change of heart and calls Yun Ding'en, raising questions about his daughter's death. This forces a chain of confessions. The truth is revealed: Zhou Shaoxiong wanted sole power and feared Yun Anna would be an obstacle. He ordered his loyal subordinate, Mo Kang, to arrange the murder. Mo Kang hired the killer and then eliminated him and all other witnesses, framing Yang Libing. Zhou Shaoxiong has been blackmailing Mo Kang ever since by threatening his daughter, Wang Juhua.
With the police force's approval to exploit this internal conflict, Yun Ding'en confronts Mo Kang. Mo Kang confesses everything, expressing his bitterness over being passed over. Ordered by Yun Ding'en to atone for his betrayal, Mo Kang commits suicide in front of Yun Anna's portrait. Upon hearing the gunshot and confirming Mo Kang's death, Zhou Shaoxiong wastes no time and secretly orders the murder of Wang Juhua and her family to silence any remaining loose ends.
In a final, stunning twist, Ma Yingzi reveals her true identity to Lu Shaohua. She is the wife of Yang Libing, the man who was framed for Yun Anna's murder. Zhou Shaoxiong killed her husband and her entire clan, and she has been serving him only to protect her son. Deeply moved and now sharing a common enemy, Lu Shaohua proposes marriage, forming a powerful new alliance bent on revenge.