Chief inspector of Hong Kong’s Criminal Intelligence Bureau, Cheuk Hoi, is suspicious of his close colleague’s mysterious death. Adding to the enigma, he discovers that the five undercover agents who were in constant contact with his dead friend have all vanished.

The members of a diverse vigilante group formed to boost the police's image are put in jeopardy when they stumble upon an unexpected drug deal.

Martin Hristov ist ein speziell ausgebildeter Agent der bulgarischen Polizei, der die Kreise des mächtigen Mafiabosses Djaro infiltrieren soll. Je mehr sich Martin um das Vertrauen und die Anerkennung des Untergrunds bemüht, desto mehr wird er in einen Sog aus Korruption und Gewalt hinabgezogen.

When a secret police operation fails, sniper Lee Ho-yeung develops a personal grudge towards his co-worker Ko Chun-kin. Ho-yeung eventually decides to leave the police force and becomes the president of a firearms association, colluding with organized crime on the sky. Through abusing the trust of an unknowing detective and the trust of his girlfriend who still works with the police unit, Ho-yeung has secretly been working against Chun-kin, who has been kept in the dark the whole time. But when Chun-kin starts to suspect the clues within multiple murder cases, a tense standoff between the brothers unfolds.