CID officer Lai Yat-tsau parents died early, leaving him to take care of his three younger sisters. First younger sister Lai Suk-chu is a prestigious kindergarten school superintendent who is kind but gullible. Middle younger sister Jil Lai Suk-si is a luxury brand salesperson. She is immature and money hungry. She originally dated Yat-tsau's partner Fai Chung-lim because he is a rich restaurant heir, but after years of dating she really fell-in-love with him and wants him to quit the police force because of the dangers that comes with the job, also for him to return to being a rich heir. Youngest sister Fanny Lai Suk-fan is rude and lazy, who refuses to find a job. She is also the only one in the family that is married. Her husband Ma Chi-chung works at the Agriculture, Fisheries and Conservation Department, but his attitude is very similar to his wife and often mooches off of his in-laws. Lai Yat-tsau is a reckless cop who does major damages to the streets of Hong Kong when he is chasing crooks. His recklessness drags his partner Chung-lim down with him. Together the pair are nicknamed "Faw Sui" Sir and "Fai Chia" Sir because the two are tend to start a fire. When Yat-tsau's former informant Lui Kam-bo seeks his protection from his recently released older twin brother Lui Kam-dong, that Kam-bo had helped Yat-tsau put in prison. Yat-tsau trails Kam-dong's every move to make sure he doesn't kill Kam-bo. During a drug bust between Kam-dong and his former gang, Yat-tsau gets attacked by the gangs guard dog named Bah-da. While recovering from a dog bite in the hospital his meets Ma Chi-ho, who is more concern for Bah-da then Yat-tsau's injuries. Chi-ho's political correctness and bluntness ends up offending Yat-tsau which leads to the two becoming enemies. Ma Chi-ho is a veterinarian for the Agriculture, Fisheries and Conservation Department. Her love for animals overshadows her consideration for others and her blunt know it all attitude offends people she speaks to. Due to her love for dogs she became estrange with her mother Madam Chung, who is also Yat-tsau's new supervisor, when her mother had her police dog overworked, leading to his death. Her younger brother who also happens to coincidentally be Yat-tsau's brother-in-law Chi-chung works alongside her, but he too can't stand her because she made him feel stupid when they were growing up. To prevent Bah-da from being euthanized, Chi-ho must find a reason proving he is not a dangerous dog. When Bah-da sniff out an Agriculture, Fisheries and Conservation Department employee with drugs on him, Chi-ho realizes that Bah-da knows how to detect illegal substances and recommends that Bah-da be trained as a police dog. Madam Chung also forces Yat-tsau's to transfer to the Police Dog Unit so that he can learn some disciplinary.
Agriculture, Fisheries and Conservation Department
:zh:陳嘉輝|Gary Chan as Lam Mo-nung
Eddie Ho as Kung Yan
:zh:黃得生|Ocean Wong as Lin Wai-man
:zh-yue:邵卓堯|Andy Sui as Yee Wing-kee
:zh:譚坤倫|Alan Tam Kwan Lun as Kit
:zh:陳勉良|Chan Min-leung as King Suk
Extended cast
:zh:古明華|Jerry Ku as Lui Kam-dong & Lui Kam-bo
6-Wing as Risk Liu Lee-si
:zh:秦煌|Wong Chun as Tai Sam
:zh-yue:沈可欣|Janice Shum as Jenny Law San
Liu Si-lok as Mo Ching-ching
:zh:馬貫東|Mark Ma as Siu Bak lim
:zh:罗天池 |Eddie Law as Lai Hei-bau
:zh:陳珈穎|Kerry Chan as Jackie
:zh:祝文君|Samantha Chuk as Charlie
:zh-yue:梁茵|Kiko Leung as Katie
Soundtrack
The main opening theme song "You Got Me" was sung by Linda Chung, composed by Dominic Chu and lyrics by Hayes Yeung. A Mandarin Chinese sub theme song sometimes played during the closing credits named "Listen to the Sea" is performed by The Voiceseason four participate :zh:谷微|Vivian Koo, composed and lyrics by Taiwanese composer and producer Michael Tu. ;Track listing
Development and production
Bosco Wong and Linda Chung were named as leads to an upcoming TVB drama in March 2015. This will be their second pairing together, after TVB 2012 drama Witness Insecurity.
The costume fitting and blessing ceremony was held simultaneously on June 22, 2015 12:30 pm at Tseung Kwan O TVB City Studio One Common Room.
Filming took place from June till October 2015, entirely on location in Hong Kong. Major filming locations were the Kwun Tong Police Station, Agriculture, Fisheries and Conservation Department at Cheung Sha Wan Road, Kowloon and Police Dog Unit Headquarters at Sha Ling village, Sandy Ridge, Hong Kong.
K9 Cop is Raymond Wong's first drama since recovering from Behçet's disease.
A promo image ofK9 Cop was featured in TVB's 2016 calendar for the month of June.
Viewership ratings
February 14, 2016: No episode broadcast due to airing From Vegas to Macau .