What if you had the chance to change the past? Dong-ho, a successful lawyer at a prestigious law firm, decides to practice corporate law at a pharmaceutical company. He finds his wife murdered at home after returning from his going-away party. One year after the incident, Dong-ho, who is now in ruins, receives a phone call from his deceased wife. He soon realizes that he is on the phone with his wife on the day of her murder. Dong-ho attempts to change the present as he steers his wife through the murder attempt. Will he succeed in helping his wife survive? Who is behind this murder attempt?