Armed Reaction

Chu So-Ngo works leisurely behind the desk at the police station. However, things took an unexpected turn when her boss's wife thought So-Ngo was having an affair with her husband and transferred her to the Patrol Unit. Soon she learns her happy marriage is not as perfect, when she finds out her husband has a kept mistress and plans to divorce her. She switch for desk duty to on the beat duties for better pay. As a beat officer, she gets to know Inspector Chan Siu-Sang (Bobby Au-Yeung). The two have a close friendship and soon starts developing feelings for each other. Chan Siu-Sang's niece Chan Sam-Yuen, is a tomboy who has always dreamt of becoming a cop like her uncle. Since she is so active in her job, her superior Ching Fung writes her up for being too ambitious and unruly. While always bickering, Sam-Yuen and Fung soon find out they also have similar interests. When Fung's girlfriend leaves him for her ex-boyfriend, Fung soon starts to fall for Sam-Yuen.

Chu So Ngo (Esther Kwan) has been promoted to sergeant rank in the police but she encounters professional setbacks due to her new responsibilities. She depends on fellow cop Chan Siu Sang (Bobby Au-Yeung) who is now her boyfriend for support and a secure future, and hopes for him to get promoted soon. They plan to get married. Sam Yuen (Joyce Tang) and Ching Fung (Marco Ngai) are also experiencing difficulties in their new marriage when San Yuan is transferred to the Special Police Unit and concentrates more on her career than starting a family.

A year later, Chan Siu Sang is single and all alone; his old love, Chu So Ngo, married the doctor who treated her son and left the police force. Then, he meets Wai Ying Zi, a rookie police officer who is under the Chan Sam Yuen Police Traffic Department unit. The two get off on the wrong foot due to misunderstandings. Wai Ying Zi, who is eager to show off her skills, seems to get into a lot of trouble. She is deemed reckless and rash. Later on, Ying Zi joins Siu Sang's CID unit, which leads to the two bickering Non-stop. After Siu Sang saves Ying Zi's life during one of their investigations, she learns to respect him, and the two become friends. Chan Sam Yuen is promoted to the head of the Police Traffic Department. She and Ching Fung are also now parents to a pair of girl/boy twins, but their marriage is not as happy as it seems as the two continue to have quarrels in their marriage. With marital problems at home, Sam Yuen becomes a cold, unreasonable and mean boss at work.

Chan Siu Sang and Wai Ying Zi have been dating for a while and seem to be in a stable relationship. Everything seems to be looking up for Ying Zi now that she's in a stable relationship and finally got a promotion at work, but the only that she and Siu Sang seem to fight about is marriage. Their relationship is further complicated when Siu Sang becomes jealous of Ying Zi's new handsome co-worker Ken. Mad that Siu Sang does not trust her, the two decide to break up. Ying Zi soon starts dating Ken since the two grew close while working together, and Siu Sang begins dating Sunnie, who works in the forensic department, after being pursued by her. Having gone through so many tragedies in the past, Chan Sam Yuen finally decides to focus on her family as a top priority. She and Ching Fung have patched up their marriage even though it is still not perfect. With a difficult pregnancy, Sum Yuen is no longer focused on her career.