Su-ah and Seo-jun are a married couple of three years. On the day of their wedding anniversary, Su-ah finds out that her younger sister, Eun-ah, has returned to the country and is in the same bed as Seo-jun. Shocked by this, Su-ah demands a divorce from Seo-jun and returns to her status as the CEO of Madly Group. Then, in the process of taking revenge on Eun-ah and the people around her who tormented her, she clears up deep misunderstandings with Seo-jun, and their relationship becomes good again.