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”…

Chan Zhan Tung, was originally the owner of the "All-Knowing Detective Agency". The company subsequently changed hands, and Cheung Lok Hang seized all rights. Lee Jin Hiu then joined the company. Chan Ka Hei, Cheung Lok Hang, and Lee Jin Hiu later changed the position of the detective agency from a detective agency that purely collects evidence for customers to "Unlimited Generation Slash".

Ouyang Jun, a Hong Kong professional boxer, has set an unprecedented record in Hong Kong professional boxing, and his popularity has never been better. Personality is not good at chatting, stubborn hard work, never give up easily. A few years ago, because his brother Ouyang was running away from home to avoid debts, Jun took refuge in his brother's friend Lu Jian in the King Boxing boxing gym. Since then, the boxing gym has become Ouyang Jun's second home. In the boxing gym, he met his friend trainer Li Chengdong and Jiang Xiuxian, a girl from the neighborhood laundry. Ouyang Jun made up his mind to become the Asian boxing champion due to the teaching and sudden retirement of the big brother Yuan Tianjiu in the boxing gym, hoping to bring glory to the boxing gym.