Mainland CID Officer JIANG ZIDAN (Wang Yang), nicknamed “BULLET”, infiltrates a Hong Kong triad group in an attempt to investigate a cross-border drug trafficking case and encounters Hong Kong narcotics inspector WAI CHUN-HIN (Him Law) and female officer CHAN YUET-KI (Cecilia So). The swift and smart BULLET is favoured by the triad leader WU KOON-YAU (Damian Lau), but he is not aware that CHUN-HIN is the trusted one of the triad’s deputy leader HON LONG (Gallen Lo). The kidnapping of WU’s daughter WU KA-LAM (Jolie Zhu) quickly stirs up long-standing conflicts between HON LONG and KOON-YAU and further fuels their antagonism. CHUN-HIN employs police resources to rescue KA-LAM without authorisation and is dismissed, but in secret he still keeps in touch with narcotics officer SO CHING (Toby Leung). HON LONG, trying to arrogate all the power, does all he can, even in collaboration with outsiders, to get rid of any opposition or possible threat. On the surface, he works closely with BULLET and CHUN-HIN, but what lies underneath is indeed immeasurable power struggle, causing endless rivalry between the good and the evil, among these “frenemies”…

In this prequel to the original, a bloody power struggle among the Triads coincides with the 1997 handover of Hong Kong, setting up the events of the first film.

While Yeung Kam Wing is trying to remove all connections between the mob and him, his actions are being carefully observed by Lau Kin Ming, who bears a personal grudge against him.

During the 1944 Wang Jingwei regime of the 2nd Sino-Japanese War, Lu Feng, an orphan, returns home to Shanghai after studying for two years in Japan. Unbeknownst to the world, he has been ordered to enter the No. 76 Headquarters as an undercover agent for the Communist Party. Along the way, Lu Feng encounters the mysterious Hua Xiang Yu, a capable and skilled woman who has just returned from studying abroad in America, and his old childhood friend, Huo Fei. Both individuals seem to hold secrets of their own. Time and time again, as Lu Feng strives to protect his undercover identity, he finds himself on the opposite side of Hua Xiang Yu. Slowly and uncertainly, the two circle around each other, each hoping to uncover the other's real purpose. In this time of chaos where corruption and violence dominate the world, these underground agents, can only choose to fight for what they believe is right... and, hopefully, bring about a more peaceful tomorrow.

Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.

End of 1946. The Kuomintang army encircled a group of the People's Liberation Army in the southern part of Henan. In order to delay the enemy's attack and ensure the safe transfer of the people, our love workers decided to use false information to confuse the enemy. Deng Yuanda successfully penetrated into the enemy's interior. Fighting wits and courage with the secret agents headed by the director of the intelligence department, Fei Siqing, and successfully completed one task after another. Through continuous combat experience, Deng Yuanda has matured and eventually grown into an outstanding intelligence worker. The initial difficulty in communication has gradually changed to mutual understanding, trust, acquaintance, and love. Just at the last moment when they completed their mission and were preparing to evacuate, Ye Shuting heroically sacrificed. After completing the mission, Deng Yuanda continued to move toward a new battlefield with their common ideals.