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