It is 1963, and the police of Kurashima City have spent the past seven years eradicating the Yakuza gangs which have caused so much strife in the city. The last two remaining gangs, Ohara and Kawade, are in tatters, with the Ohara Boss in prison. But with the police force full of corrupt officers, the gangs begin to flourish once again. The Kawade gang, sensing the opportunity to strike their enemies while their leader is incarcerated, decide to stage a raid on a club owned by their rivals, but the attention of the police is drawn to both gangs again. Ken Hirotani is running the Ohara gang while the boss is in jail, and he soon discovers that a childhood friend, Kuno, is now a police detective assigned to clean up the underworld. But Kuno's loyalties lay more with his friend than his career, and his honour is tested time and time again. When a major property deal goes bad, the police are able to persuade the two gangs to come to a truce, but there are elements of both sides who don't like what their superiors are negotiating. Soon it's not only Cops vs Cops, as loyalties are strained and honour pushes the boundaries of the law, with an epic showdown looming.