Unable to satisfy his sexual desires with his wife, Bill regularly visits prostitutes. Afterwards, he ties up and tortures them in various ways before killing them. Bill believes that if they die, they will be reincarnated and have a better life. He murders over a dozen people. One day, a young woman named Jade comes to stay with Bill's family. He falls in love with her but is afraid that he will kill her, so he makes her leave. Jade has nowhere to go and starts working as a prostitute. When Bill finds Jade doing this, he has sex with her and gets her pregnant.
Unfortunately the movie Diary of a Serial Killer is not yet available on Disney Plus.
| Directing | Norman Chan | Director |
| Sound | Yau Ning Wong | Sound Effects Editor |
| Crew | Cheung Man-Po | Cinematography |
| Editing | Angie Lam On-Yee | Editor |
| Writing | Philip Cheng Chung-Tai | Writer |
