This is a story about Hong Kong Customs. The trio comprising Intellectual Property Investigation Bureau Senior Superintendent Hoi Fung, Trade Controls Bureau Chief Trade Controls Officer Kwan Pui-yan and Customs Drug Investigation Bureau Superintendent Wan Tsz-ki lead a contingent of elite customs officers and fresh-faced rookies, including Probationary Inspector Chan Ka-hing, to carry out diverse operations involving eggs, nuclear bombs, baby formula, heroin and much more. They are always ready to go all out not only on the ground, but also in the sky and at sea, showcasing a reinvented and ingenious Customs and Excise Department. This group of individuals adhere to the motto “Serve the Community with Commitment and Excellence”. Although they have their own issues, they can still overcome hurdles. They contribute to social stability and prosperity in Hong Kong, and Hongkongers are proud of The Line Watchers.

Yeung Pik Sum suffers from Schizophrenia and her illness causes her son, Yip King Fung, to suffer from Dissociative Identity Disorder. King Fung’s split personality, Chu Kei, becomes a handwriting expert and criminal profiler, who helps King-fung, an undercover agent, to uproot a criminal organization. However, a series of strange cases makes King Fung a murder suspect and his younger sister to be traumatized. Feeling guilty about abandoning her children, Pik Sum becomes a mental hospital assistant to protect her daughter, but she is unable to reconcile with King Fung... Superintendent Lip Shan invites King Fung to join the Special Crime Unit. Together with psychiatrist Wai Yui Kit, bomb disposal expert Yau Ngan Sing, forensic anthropologist Fong Yuen Chin, they deal with criminals with abnormal psychological conditions and solve complicated cases.

After absorbing supernatural powers that saw his powers increase tenfold, taxi driver Ma Gwai continues on another adventure as a past incident involving a childhood friend comes back to haunt him. Ma Gwai's childhood friend Ho Zai died

Emergency Unit senior female sergeant Lui Fei-hap is over 30 and had her ups and downs in love. When she meets the perfect man, she actively began her 'hunt and capture' operation, but unexpectedly discovers that her boyfriend's true identity is, in fact, a drug lord. Her entire relationship with this drug lord was captured and placed on the headlines by tabloid reporter Lam Yat-yat. Fei-hap's and Yat-yat's paths continue to cross when pursuing duties and stories, sometimes co-operating and sometimes as enemies, sometimes saving the other and at other times the target of each other's practical jokes. Before long Fei-hap finds herself falling in love with new recruit Wong Tze-tsuen, only for Yat-yat to stand in her way again. Pushed to her limits both at work and in love, Fei-hap has no choice but to fight back in the name of love.

Tiger Cubs, alternatively titled Special Duties Unit, is a Hong Kong police procedural television series produced by Lam Chi-wah and TVB. It premiered on Sunday, 24 June 2012 on Jade and HD Jade, and was the first TVB drama to broadcast in the Sunday night time slot since 1995's File of Justice. Tiger Cubs was one of six TVB dramas that were promoted at the 2011 Hong Kong Internal Film and TV Market. Tiger Cubs debuted its trailer at TVB's Programme Presentation 2012 event on 1 November 2011. The drama is renewed for a sequel in early 2013, with a production of 20 regular episodes. Filming for the second series began in June 2013.