Yeomin Chae has been living in the shadow of her stepsister, Nari Chae, ever since they were kids. One day, Seungjae, Yeomin's ex-boyfriend, tells her that he’s marrying Nari out of the blue. After being betrayed by the person she trusted most, she runs into Hwan Yun, who is the grandson of Taeju Group’s chairman. Frustrated with her life, she suggests to Hwan that he marry her. As the two decide to get married, what exciting events and struggles will they encounter?