A car accident wipes Bai Yu’s memories of everything she went through before. Then a marriage certificate brings Sang Mu into her life. Bai Yu thinks that if they agree on three rules, they can live peacefully through the three-year contract and then part ways, becoming strangers again if they ever meet. But she realizes that Sang Mu’s concern for her is no longer anything like that of two people who have only just met. By chance, Bai Yu discovers in his study just how closely he has followed every detail of her life before they met. She grows suspicious of him and investigates further, only to find herself caught up in an even greater mystery.
