Hyeong Ju is a violent crime detective who lives a contented and fulfilling life but is given the mysterious opportunity to go back in time. Ga Hyeon is a famous webcomic author known for her mystery thriller stories. Unfortunately, a workaholic and perfectionist, Ga Hyeon, suffers from a terrible accident and receives the same offer to go back in time. In addition to 8 other individuals, the two of them reset their lives for the better but quickly begin to uncover a series of mysterious events that threaten their future.