In the Line of Duty IV

A Hong Kong cop and two American cops are onto a suspected harbor worker and are forced to team up when they discover that the suspect is a witness on the run from CIA agents and their schemers; two corrupt cops.
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.