Hae-Gang (Kim Hyun-Joo) is a successful lawyer, but she wants to become more successful. Due to her ambitions, her relationship with her husband, Jin-Eon (Ji Jin-Hee), deteriorates. At that his time, Jin-Eon meets Seol-Ri (Park Han-Byul) who attends the same graduate school. Her personality is pure and enthusiastic, like his wife Hae-Gang had in the past. Hae-Gang then has an accident and loses her memory. She meets Baek Seok (Lee Gyu-Han) and live as her younger twin sister Yong-Gi (Kim Hyun-Joo)