Old Time Buddy - To Catch a Thief S1 E13

Police cop Lee Kei is assigned by his lieutenant to go undercover and find the infamous cat burglar, "Black Rose", who has escaped being captured for over twenty years. His first clue leads him to a nightclub where he bumps into a former classmate, Tse Sei. When Lee Kei is threatened with dismissal at his corrupt police precinct and his house is burnt down by triads, Sei helps him out by bringing him to live with Sei's uncle. It is through this apartment where he meets a former neighbour, Siu Fong-fong, and a martial arts performer, Cheng Po-chu. When Kei recognizes the martial arts as a style similar to what the "Black Rose" uses, he suspects that Po-chu and her colleagues could be related to the cat burglar and decides to follow them closely.