"Happy Together" portrays the daily life of the Man family, reflecting the living conditions of a typical Hong Kong family. For example, the family participates in property speculation and loses miserably, the wife works outside and causes dissatisfaction from her husband, the wife plans to invest in immigrating to a foreign country as a backup plan, middle-aged men having extramarital affairs, the wife's younger brother "Ah Chai" applies for public housing, the wife's shopping addiction, divorce between Zhu Zaibao and Dan Nao, the robbery of the Man family, Mr. Man's desire to return to mainland China for business, and Yue being forced by his mother to sell ginger as a street vendor. These were common events among Hong Kong people at the time, and the show brought these topics to television, resonating with the audience.

A big house is haunted by four ghosts. Three families moved in at different times, including Ling Da Ting and his pregnant mistress Lu Bi, the jeweler Wang Tian Xiang and his family, and the retired dance instructor Hua Luo Shi and his family. Although the house is haunted, the younger generations can communicate and play with the ghosts. Lu Bi went into labor, and the four ghosts competed to be reincarnated. Once, Lu Bi was saved by Zhuang Wei Qiang, who had a crush on her. Xiao also fell in love with Lu Bi, and they began a romance. Eventually, the three families faced eviction but became close friends after going through ups and downs together. The three families helped the ghosts reincarnate, and they tearfully said goodbye at a banquet.