Joo-Hee is a college classmate. Everyone envys Hye-won, who married her first, but Hye-won, who is not married to her, is more envious of her unmarried friends. Hee-jeong becomes frustrated with her sexist Min-woo and hands it over to her friend Joo-hee. Hee-jeong has an affair with her boss, and Hye-won and Joo-hee discuss that she should switch her husband and lover. Joo-hee seduces Hye-won's husband. Hye-won seduces Joo-hee's lover. Couples swapping couples and swapping each other.