Lee Geon is the only heir to the largest natural soap company in Korea. He signs a contract saying that he will get married in 100 days, expecting that his girlfriend, Nam Se Ra, will accept his proposal. Kim Mi Yeong is the sticky note of her company, everyone uses her and throws her away when they are done. Mi Yeong wins a trip to a resort in Macau, which happens to be the same place Geon plans to propose to his girlfriend. After a twist of events that leaves both alone and drugged on their trip, they find themselves in a one night stand. Mi Yeong soon finds out she is pregnant and is forced into a contract marriage with Geon to carry out his family's legacy.