[4][5] South Korea's most wanted criminal, "Helios" (Chang Chen), and his assistant "Messenger" (Janice Man), have stolen a weapon of mass destruction secretly developed by the South Korean military, a portable nuclear explosive device (DC8), along with sixteen fuel modules.

An emergency response team is set up, including chief inspector Eric Lee Yan-ming (Nick Cheung) of the Counter-Terrorism Response Unit, senior Chinese official Song An (Wang Xueqi), and two South Korean weapons experts: Choi Min-ho (Ji Jin-hee) and Park Woo-Cheol (Choi Siwon).

Lee invites Physics professor Siu Chi-yan (Jacky Cheung) of the University of Hong Kong to serve as special adviser for the operation.

Choi wants to hunt down Helios, take back the weapon, and ensure that South Korean military secrets are not divulged.

Lee and Siu, members of the Counter-Terrorism Response Unit, have to deal with the greatest challenge, facing pressure from both China and South Korea.