In the Line of Duty 4 is an exciting, over-the-top action film directed by the now internationally acclaimed master filmmaker, Yuen Wo-Ping. Producer Stephen Shin Gei-Yin used Yuen to give an energy infusion to the 3rd sequel to the 1985 box office hit Yes, Madam. Ultra-cool Donnie Yen Ji-Dan joins series mainstay Cynthia Khan, who reprises her role as Madam Rachel Yeung of the RHKP.

The film features some absolutely death-defying car stunts, with Khan hanging off the side of an ambulance, as well as some extraordinary martial arts sequences that are remarkable to behold. This feature marks the debut of the talented Cho Wing as an Action Director. Look for a young Liu Kai-Chi, a talented character actor in an early feature role.