The story starts with a doctor Kim Joon-young returning home. His daughter Eun-jung dies in an accident on the same day along with a woman. He wakes up and the day repeats he tries to save his daughter but fails it repeats over and over again . It was when that woman husband also repeats the day over and over again. They later found out that they cannot save their loved ones no matter what. Later they find out the father of a child whose heart was transplanted without the fathers concern and the man who had made the accident are the two person whose day is repeating along with the child father's who is seeking the revenge by killing their loved ones. They reconcile to the father after learning that his child heart inside the doctor daughter does not allow his father to die so they save him everything returns to normal. The doctor tells about the transplant to the press as the movie ends.