Because of the eradication of criminal Lu Shiming, Inspector Gu Yuan was promoted to Inspector General, and Deputy Inspector Kang Yichen had no choice but to inherit the Wanguan family business due to the death of his father. The appearance of Lu Shijun, the new director of the Public Board of Directors, made the atmosphere of the patrol room dignified, because he was not only Lu Shiming's brother, but also the fiance of Cha Suwei who had disappeared. His appearance, I don't know is to avenge Gu Yuan or to regain Che Suwei's heart. Kang Yichen held a socialite party in the mansion, but a woman died unexpectedly at the scene. According to Che Suwei's autopsy, the deceased died of heart failure, which was caused by a large number of parasites in the body, like a worm. According to the investigation, Gu Yuan found that the parasite was related to the special blood drop on the neck of the deceased. The blood pendant is a luxury item that has recently become popular in the celebrity circle, and its origin is unknown. Che Suwei found out through clues that the blood drop was related to the mysterious organization "Xinyuetang", and decided to go undercover into Xinyuetang's lair to find out.