Seon-woo and Eun-gyeol, two old friends who grew up together since their snoring days, live together with their wives even after marriage. As time goes by, the two begin to lose interest in their relationships with their wives, Ga-hee and Jeong-eun, and decide to try swapping. After swapping, Seon-woo and Eun-gyeol's friendship begins to crack, and they start to covet each other's wives at will. In the end, Ga-hee and Jeong-eun leave their husbands.