"Two Wives" tells a series of stories about a man who lost his memory due to a traffic accident, and the relationships between him, his ex-wife, and his current fiancée.
Sun Tae-young plays the role of Han Ji-suk, an unmarried mother who runs a high-end wine shop and a flower shop on her own. With a personality that lies between calmness and passion, Ji-suk fell in love with her boyfriend during her studies in the U.S. and had a child. However, she returned to Korea alone with her child without marrying her boyfriend. Despite her family introducing her to many men, these men all demanded a high divorce settlement if they were to marry and later divorce. Having already lost faith in men and decided to live alone, Ji-suk meets Kang Jeol-su (played by Kim Ho-jin) and falls in love with this romantic writer who shows no concern for money. As a full-time writer, Jeol-su is a struggling author who doesn't even have a representative work and makes ends meet by working part-time as a university lecturer and writing essays, with his household finances controlled by his wife, Yoon Young-hi.
After being married to his wife for ten years, feeling that his wife only cares about money, Jeol-su gradually drifts away from her. In order to gather material for his novel, Jeol-su participates in an online "borrow a husband" activity where he meets the unmarried mother Ji-suk and begins to feel something for her. After divorcing his wife, Jeol-su starts a new romance with Ji-suk and they plan to get married. Unexpectedly, Jeol-su encounters a traffic accident before their wedding, suffers severe injuries, and after being unconscious for a month, wakes up suffering from amnesia. The amnesiac Jeol-su only remembers his ex-wife Yoon Young-hi (played by Kim Ji-young), but forgets his current girlfriend Han Ji-suk, leading to an awkward and complex situation among the three. Yoon Young-hi's immature younger brother Yoon Nam-jun (played by Andy) is an idle and unemployed loafer who, despite his polished appearance, is nothing more than a troublemaker. He will engage in a May-December romance with Zhao Mei-mei played by Lee Yu-jung.