The Diary of a Husband serves as an illustration for the arrival of the white-collar economy, in which the extended family is replaced by the smaller nuclear family. It is a story about four pals who work at the same office, which, like other white-collar workplaces, has become the men's primary site of life, where livings are made and friendships fostered. Meanwhile, their wives have fostered something of their own—a brigade to catch cheating husbands. Much comedy is then generated by the cat-and-mouse game between the men and the women...The battle line drawn here between the sexes remains for years, to the extent that this very same story has been retold many times in Hong Kong films, including Men Suddenly in Black, the 2003 Pang Ho-cheung film with a similar Chinese title.

Chan Siu-hung is forced to become a prostitute, with the police following hot on her heels. Ching Chi-ko comes to her defence by claiming to be her husband. Chan is put up at Ching's roof hut named the 'Seventh Heaven' and the two gradually fall in love. Soon the war breaks out. Ching is drafted to do hard labour by the Japanese army. When the war is over, the crippled Ching returns and lies to Chan that he is already a married man, hoping to persvade Chan to marry someone else. Nonetheless, Chan's devotion overwhelms Ching.

The town is rumoured to be haunted. Cheung Siu-chen pretends to be possessed so that her lover Lau Tin and his friend Lee Luk may heroically exorcise the ghost and curry favour with her father. Driven by greed and lust, the attendant of the ancestral temple and his underlings cast an enticing spell on Cheung and claim that Cheung is possessed with a fierce ghost. Lau and Lee expose the hoax and redeem Cheung. Cheung's father happily gives his consent to the marriage between his daughter and Lau.

Yuk Yin's father dies and her mother remarries to settle the debts. Yuk Yin lives with Auntie Wong. From then on, Chi Hung, Auntie Wong's son and Yuk Yin live and play together. But the Wongs move away. Yuk Yin stays with her mother. Her stepfather is mercenary. When Yuk Yin grows up, he pushes her to get married to get money. Considering her daughter's future, Yuk Yin's mother sends her away. Yuk Yin works in a restaurant. When she learns that her mother is ill, she marries a dying rich young man to get money for her mother's treatment. After her mother's death, Yuk Yin gets married immediately, but her husband dies on the wedding night. Her mother-in-law sees this as unauspicious and expels Yuk Yin. Later, Yuk Yin chances upon Chi Hung. They are still in love. They married and have a son Kwok Wah. But Chi Hung dies. Yuk Yin works as a dance girl to support their living. Kwok Wah grows up and cannot accept his mother's job. But soon he understands that she is respectable.

Reporter Yu Mong-yuen is recovering from a leg injury in his fiancee Man-wah's apartment. Bored, he looks out the rear window and observes the life of the neighbouring building. Among the tenants are a sugar-daddy and his mistress, a middle-aged man wants to marry a young girl, but she is in love with his son. Finally, she hatches a plot and makes the man agree to her marrying his son ; a sly fortune-teller ; a lively gym, a rich widow quarrels with the trainer of a gymnasium because his dog has bitten her cat ; and an opera school, a woman signs, leaning on the balcony, and a man tries to strangle her. In fact they are rehearsing an opera…… One evening, Wah is on the night shift, and Yuen watches the opera troupe rehearse to the end. Under the influence of drugs, Yu mistakenly believes that a divorced man has murdered a taxi dancer. He alerts the police, but the whole thing is nothing more than a misunderstanding.

In order to wait for her lover Fan Chun-tak to finish his study in Australia, Tang Sau-man works as a governess in Chui Shek-wah's house. Chui is Fan's brother-in-law. Chui spoils his wife Fan Kam-ping. She becomes lazy and dependent on Tang. Fan finishes his study and returns. He decides to transform his elder sister. He asks her best friend, Pang Shui-ha, to persuade her. Pang has a crush on Fan. Pang uses this opportunity to get intimate with Fan. Tang originally thinks that after Fan comes back, she no longer has to live in somebody's shelter. But Fan spends all his time with Pang. Tang is unhappy and drinks to vent her unhappiness. Tang gets drunk and Chui takes care of her. However, Ping thinks that they have dubious relationship and throws Tang out. Tang falls down a slope and loses one leg. Fan is angry with himself and decides to marry Tang. Ping also realises that she is wrong. She decides to change her lazy character and takes care of the disabled Tang.

Lawyer Fan Kam-man believes that his wife Chun Yuen-yung perished in a plane crash three years ago and walks down the aisle again with Yan Bik-kei. In fact, Chun survived a crash-landing on a deserted island with fellow passenger Wong Ah-lik, a biologist. Returning to civilisation, Chun sabotages their wedding night at the hotel. Overjoyed with her safe return, Fan pulls off a feat with his mother and wife to terrify Yan into divorcing him. However the lie is exposed when Wong shows up. Unyielding, the women settle to serve as wives to the same man. Mistaking Fan for the person Chun is going to see, the eavesdropping Yan goes to the date in her stead and unwittingly sleeps with Wong. Yan finally settles for Wong, putting an end to the topsy-turvy.

Orphan Lee Dan-hung is made a scapegoat by her cousin Chor Kwai-ping. Facing drug trafficking charges, Lee is released on parole with the doctor To King-chung as guarantor. Lee works as a sanatorium nurse. The modest caretaker, Matriarch To plays matchmaker for her son To Ngan-sing and Lee. Ashamed of her past, Lee listens to the doctor's advice and keeps the Tos in the dark. Chor returns and coerces Lee into colluding with smuggling ring by threatening to kill her newborn daughter. The reluctant Lee is arrested in a police raid together with the gang members but is later acquitted. With a reputation to defend, To toughens his heart and expels Lee. Lee leaves for Borneo with a touring opera troupe but a yearning for her daughter brings her back several years later. Feeling for the upset in-law, Matriarch To grants her stay until his son's return from business in a few months' time. When To returns, he decides to make up for the wasted time by bringing Lee and her daughter home.

Ho Pui-lan was the secretary of the writer Wu Him, but she died suddenly at home. Ho's mother commissioned private detective Chan Kin-chau to investigate and found out that Pui-lan and Him were having an extra-marital affair, and also discovered that the contents of Him's fiction were similar to the contents of Pui-lan's suicide note. When Kin-chau finds out that the contents of Him's fiction are similar to the contents of Pui-lan's suicide note, he and Pei Lan's sister Yuk-lan reenact the murder case, and Him is stimulated and hallucinated to reveal the truth of the murder...