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.

An oriental doctor Kim Hak-gyu is a cantankerous man who is the longest-term householder in a small village in Seoul. He often causes domestic trouble by being nasty to his wife and his children. Kim Hyeon-ok, a daughter of a young widow who runs Nahana Beauty Shop, is in love with Choi Du-yeol, an obstetrician across the street. Kim Hak-gyu has great distaste for western medicine, and at the same time, is jealous of the obstetrician. He always gets in the way of Choi Du-yeol. Kim's son, Hyeon-gu, dates Jeom-ryae, a daughter of a bar owner.

Prior to his world title match, In-du dies in a car accident. When his spirit reaches the afterworld, they send him back to the real world because it's not his time yet. In-du is reborn as President Choi Mun-oh who was poisoned by the executive director Sam-ryong and his wife Chun-sim. When the resurrected President Choi suddenly starts to box, Sam-ryong believes that President Choi knows of his plotting and is trying to kill him.

Ok-Nyo, daughter of poor but noble family, falls in love with a young noble man Mr. Jeong. Hyang-A, daughter of chief of district, is so jealous that set a fire in Ok-Nyo's house using her father's power. Ok-Nyo and her family helplessly die. Mr. Jeong has to marry to Hyang-A because he is forced to do so by chief of district. Every night Ok-Nyo's resented spirit appears in the disguise of Hyang-A to torment Hyang-A. After the days of terrible horror, Hyang-A regrets what she did and comes back to Mr. Jeong.

A space creature named Wangmagwi lands on Earth in a flying saucer with plans to dominate the planet. Koreans of every corner of the world battle against the colossal invader as it wreaks havoc across the land.