Without an official spy organisation, Japan is seen as a hotbed for crime by foreign and domestic criminal groups. K13 is a unit established within the Tokyo Metropolitan Police Department to combat this situation. The activities of K13 are known only to a few people and its members do not exist on record. Led by the top agent code named Mirage, K13 members target not only brutal crimes but are also given secret missions to handle crimes which cannot be solved politically and socially. Meanwhile, there are people who intend to set up a police organisation like the FBI in the US and strengthen the Japanese police by enacting a bill to expand its powers. Before long, the K13 gets embroiled too and a huge conspiracy is revealed.