The story is set in the 1960s Hong Kong. The sincere Ko Tai Hei smuggles to Hong Kong, where his father's good friend Kam Lo Yik recommended him to join the police force. One time, he had an accident and got shot in the head. Pieces of the bullet went into his brain cells and oddly increased his IQ significantly. Since then, Hei turned into an intelligent detective capable of cracking down strange cases. However, his personality changed as well, turning him into a cold-hearted person who will do things by unscrupulous means.
Aiming to become the best tour guide in the industry, Ng Ka-yee sets up a travel agency with his girlfriend Szema Shuk-ching but he goes bankrupt and owes a huge debt after being cheated by others. Ka-yee wishes to pass the last few months of bankruptcy peacefully and start a new chapter with Shuk-ching after marriage. However, Shuk-ching falls in love with his best friend Ching Siu-shan and Ka-yee is devastated. During this time, Ka-yee runs into the newly immigrated social worker Yik Suet-fei, his Dongguan cousin Choi Sum who dreams to be a singer in Hong Kong and the old singer Monrole who is looking for free meals everywhere. In addition, his younger sister Ng Chi-ching also returns to Hong Kong by lying to him that she has completed her master's degree in Taiwan already. Different cultures and lifestyles between Hong Kong and mainland China create family farce every day.
The 1930s Hong Kong is the time of the East and West cultural shock. Women started fighting for their rights and status, changing the 'men superior to women' image. Famous barrister Sir Arthur Chung studied in England and lives a British lifestyle, but inside he's actually a traditional Chinese man. He married several wives to show off his power and upper-class status. First wife Koo Sam-lan was a rich girl; second wife is former Qing dynasty princess Aisin Gioro Yee-yin; third wife came from a family that owned banks Yvonne Yik; fourth wife is a famous Peking opera singer Hong Tsz-kwan; and the fifth wife Chui Dan-dan, a vanity admiring woman. Because Sir Arthur Chung is a strict and authoritarian father, his two sons Charles Chung and Jimmy Chung eventually start going against him. This wealthy and prominent family may seem warm on the surface, but in reality, they are scattered and disunited.
Set in the late 1930s to late 1940s in Canton, Republic of China during World War II, No Regrets is an epic drama that centers on a triad family, the Canton police force, and the Japanese occupation of the city.
Wong Ka-Nam disappeared to the United States, leaving behind her son and husband in Hong Kong. When her husband dies in an airplane accident looking for her, Wong Ka-Nam's son, Luk Chit is taken into the custody of her mother-in-law, Ng Hang. After eighteen long years, Wong Ka-Nam wishes to see her son again and returns to Hong Kong. However, she is met with adamant resistance from her mother-in-law, who views Ka-Nam as bad luck, blaming her for the death of her son. Highly protective of her grandson and fearing that Wong Ka-Nam will attempt to take him away, Ka Nam's mother-in-law does everything in her power to keep mother and son apart. However, Wong Ka-Nam is ironically assisted by her own son, who befriends her and secures her office job in his advertising agency.