Two detectives who are up to their necks in trouble and in each other's face, as they try to shut down a drug-trafficking scheme that could be connected with international ties to organized crime. But in the midst of their investigation, innocent immigrant dock worker Luk Wan-Ting gets caught up in the mix when he witnesses the murder of an intelligence operative and is framed for the crime.
Is In the Line of Duty 4 on Netflix? Unfortunately the movie In the Line of Duty 4 is not yet available on Netflix.
| Directing | Yuen Woo-ping | Director |
| Writing | Kim Yip Kwong-kim | Writer |
| Crew | Cho Wing | Martial Arts Choreographer |
| Writing | Cheung Chi-sing | Writer |
| Writing | Stephen Shin Kei-yin | Writer |
| Crew | Sunny Yuen Shun-Yi | Martial Arts Choreographer |
| Crew | Paul Wong Kwan | Martial Arts Choreographer |
| Writing | Anthony Wong Wing-fai | Writer |
| Crew | Yuen Woo-ping | Martial Arts Choreographer |
| Production | Dickson Poon Dik-Sang | Executive Producer |
| Production | Stephen Shin Kei-yin | Producer |
| Sound | Richard Yuen | Original Music Composer |
| Sound | Tang Siu-Lam | Original Music Composer |
| Camera | Au Kam-Hung | Director of Photography |
| Camera | Ma Koon-Wah | Director of Photography |
