In this action spectacle, a car crash sparks a war between local police and an international terrorist organization. After Superintendent Yip (Francis Ng) and Inspector Ching (Nick Cheung) arrest a hacker named Yiu involved in the accident, the two police officers are suspected by Superintendent Cheng (Louis Koo) as double agents. Clues lead the three officers to the far foreign soil of Myanmar and Spain, but as the investigation continues the lines between good and evil become blurred. This sequel to the critically-acclaimed and box-office smash Line Walker (2016), starring three award-winning actors, continues to explore the emotional world of heavyweight police action.