During a promotion ceremony for police officers, Senior Superintendent Ko Yat-tai is taken hostage. Seeing his father in danger, OCTB Senior Inspector Marcus Ko Ka-chun is unable to do anything. In a split second, Yat-tai’s eldest son Vincent Ko Ka-long, a member of the Flying Tigers, demonstrates his excellent marksmanship to save him, which unexpectedly acts as a trigger to bring what was buried in the Ko family back to light. A recent spate of murders of undercover cops, a surge of new drugs, and terrorist groups are a portent of a menacing future that Superintendent Lip Yu-hong relentlessly fights against. Meanwhile, caught in their own relationship dilemma, two brothers, Ka-long and Ka-chun, end up going their separate ways, turning into rivals...