Nam Woohyun has been enjoying his life with his girlfriend, Soo Jiyeon. When something happens to Jiyeon, Woohyun would do anything to find out. Suddenly, a dark angel comes. His name is Sungkyu, a guardian who can go back in time and let people see their loved ones' past or death. Woohyun signs an agreement to see her death only with the angel and the journey begins. On the way, Sunggkyu changes his mind and goes back to the day Jiyeon was born. What will Woohyun see?