Fashion designer Soo-yeon is an attractive and talented as well as sexy woman who is always working and doesn't care for marriage. Then one day she suggests to her boyfriend, Cheon Tae-pyeong, to live together on a contract. She writes down the conditions of a contract that involves the fact that they sleep together once a week. Then one day, Yoon Min-woo, a wealthy plutocrat who used to be Soo-yeon's boyfriend, shows up and he tells her he wants to start over with her. She hides the fact that she's living with Tae-pyeong and dates Min-woo. Tae-pyeong soon senses something's up when Soo-yeon starts arriving home late and refuses to have sex. Soon after, Soo-yeon breaks up with Tae-pyeong and asks Min-woo to marry her, but she can't help but feel something missing inside her...