Zhang Hai Feng quits his job as a police officer after the death of his daughter, Duo Duo. However, one day, a serial killer case reveals new-found evidence about the accident that led to Duo Duo's death. In order to find out the truth, Zhang Hai Feng starts to pursue the serial killer and in the process, dies together with him. When he wakes up, he finds himself back in the past; one day before his death occurred. He decides to make use of the wormhole and save Duo Duo from her death. Eventually, he starts to unravel deep hidden secrets of the people around him and the web of conspiracy that was planted 20 years ago.