The drama follows a fictional team of elite paramilitary officers from the Special Duties Unit of the Hong Kong police force. They specialise in counter-terrorism, hostage rescue, and crimes that are deemed too dangerous for regular police to handle. The unit works closely with the Organised Crime and Triad Bureau (OCTB) to crack down on terrorist groups.

It is the sequel to Tiger Cubs, which was aired in the summer of 2012. The series follow a fictional team of elite paramilitary officers from the Special Duties Unit of the Hong Kong police force, a team that specialises in counter-terrorism, hostage rescue, and crimes that are deemed too dangerous for regular police to handle.