Myeong-ho (Hwang Hae), a middle school teacher who had grown up in poverty, and Bu-nam (Yang Hun), the first son of the president of a trading company, attend the same university. A doctor suggests that Bu-nam, who is sick due to overeating, and Myeong-ho, who suffers from malnutrition, should switch life styles for two weeks. While living in each other's house, they fall in love with each other's younger sister and get married at a joint wedding ceremony.
Oh starts working at a boutique to help her make a living. Professor Jang begins dating the typist Miss Park, but decides to break up with her to protect her family. Han's wife anonymously sends a letter to Jang to reveal Oh's affair.
Gwang-pil (Lee Ryong), Dal-su (Choi Bong) and Sang-mun (Choi Myeong-su) are gangster boys who pick pockets. Ae-ran (Do Geum-bong), who works at a bakery, and Gwang-pil have known each other from childhood and are lovers. The three gangster boys rob a US army warehouse, but only Gwang-pil is caught and placed in a juvenile reformatory. Hearing that Ae-ran works as a barmaid, Gwang-pil escapes from the reformatory to see her. While Gwang-pil meets her, he is caught by a cop who has been chasing him.
