Da Zi (played by Zhao Da) was an external technician sent to Hua Zai's (played by Luo Dahua) drug manufacturing group. He was sent to the Golden Triangle by Zhao Tianyi (played by Zhao Yi) as an undercover agent under Hua Zai a year ago. Unexpectedly, his identity was discovered by Hua Zai. During the crisis, Da Zi killed the drug maker who made the new drug formula, and thus became the only person in the entire Golden Triangle who mastered the new drug formula. Based on this, Hua Zai not only did not kill Da Zi, but also reached an agreement with Da Zi at a high price. At the same time, he asked Da Zi to kill his comrades who came in undercover and become brothers with Da Zi. From then on, Da Zi's retreat was cut off, and he was determined to join Hua Zai and gradually lost contact with his superiors. Zhao Tianyi came to the Golden Triangle with a conflicted mood and activated Dalu (played by Zhang Lu), the second-in-command of another local drug trafficking group. It turned out that Dalu, Da Zi and Mao Le were once the three most capable men of Zhao Tianyi, but in the process of being sent to the Golden Triangle undercover, Mao Le's identity was exposed and was killed by Da Zi himself. Da Zi and Dalu went through untold hardships and survived nine deaths to infiltrate the two major drug trafficking organizations, Hua Zai and another drug trafficking force, Hao Ge (played by Wang Gongyi). Dalu rescued Hao Ge from Hua Zai's gun to gain trust. In order to repay Dalu's life-saving grace, Hao Ge not only married his sister Amy (played by Su Mengmeng) to Dalu, but also handed over the family business to Dalu for management. There was also a Burmese man named Ajin who escaped from prison together. Ajin seems to be honest and dull, but he is actually an undercover sent by the Myanmar police. Ajin and Dalu have a good relationship, but they don't know each other's undercover identities.