During an armed robbery operation, the Yuen brothers - Dragon (Louis Cheung) and Mo (Andy On) - unknowingly walk into a police trap set by the East Kowloon Regional Crime Unit, led by Emergency Unit commander Ben Cheng (Alex Fong). The mission ends in tragedy when an undercover officer is killed and several officers are severely injured. Ben is demoted following the failed operation, while the surviving criminals escape and swear revenge. Three years later, Ben now serves quietly in an Emergency Unit patrol team, keeping strictly to procedures and avoiding unnecessary risks. His routine changes when Wallace (Carlos Chan), the younger brother of the fallen undercover officer, joins his unit. When the criminals reappear and launch a new wave of violent robberies, Wallace becomes determined to capture them at any cost. Forced to confront his past mistakes, Ben must reunite with former colleagues and face his enemies once again in a final explosive confrontation.