在这部三等课长剧情片中,Gu (Kim Seung-ho), who manages the eastern branch of Samcheolli Transportation Company, is the head of a large family comprising his father, his mother (Bok Hye-suk), his wife (Joo Jeung-nyeo), his son Yeong-gu, and his daughter Yeong-hui (Do Kum-bong). On the very day Yeong-hui starts her new job at his office, Gu is humiliated by Director Song (Kim Hee-gap), who berates him in front of his daughter. One day, Song asks Gu to convert the second floor of the branch office into a dance school for his mistress Myeong-ok (Yoon In-ja). Gu complies, and is promoted to the head of the welfare department at Samcheolli headquarters. Meanwhile, Gu's daughter Yeong-hui sees Gwon O-cheol, who works in the welfare department, meeting Myeong-ok at a coffee shop, and spreads a rumor about their supposed relationship throughout the company. In fact, Myeong-ok and Gwon O-cheol are merely relatives, and the latter had been advising Myeong-ok to end her relationship with Song. At the end of an intense argument, Song lies to his wife that Myeong-ok is Gu's mistress. Furious, Gu's and Song's wives storm into Myeong-ok's house. Song happens to be there, taking a bath, and Song's wife discovers him in the act. Gu's wife realizes that she was mistaken about her husband and returns to her home. Myeong-ok decides to end her affair with Song and go back to her hometown. Learning the truth about the entire incident, Yeong-hui apologizes to Gwon O-cheol and the two make peace.
When his wife sees him helping his boss' lover, a low-level manager finds his marriage in shambles
