Under Cover(卧底归来)

Police officer Bao Yu is working undercover as drug dealer Jin Fei's subordinate and is eventually able to work directly under powerful drug lord Tian Jing after befriending his daughter, Tang Guo. However, Bao Yu is not fighting the drug cartel alone - he also has a support network including fellow undercover colleague and romantic interest Guan Xiao Zhi, police chief Fang Qing Long and anti-narcotics team leader Lian Zhong.