Professional assassin O has resided in an isolated world of killing and loneliness. But his life begins to change once he meets the innocent Chin; hired to clean O's apartment. However, soon the flamboyent and reckless Tok enters Chin's life with a mission to unveil O's identity and usurp his place as the number one sharp-shooting assassin in the game.
| Directing | Johnnie To | Director |
| Directing | Wai Ka-fai | Director |
| Writing | Pang Ho-cheung | Novel |
| Writing | Wai Ka-fai | Screenplay |
| Writing | Joey O'Bryan | Screenplay |
| Production | Andy Lau | Producer |
| Production | Johnnie To | Producer |
| Production | Wai Ka-fai | Producer |
| Production | Shirley Lau Yim-Ngo | Executive Producer |
| Sound | Alex Khaskin | Original Music Composer |
| Sound | Guy Zerafa | Original Music Composer |
| Camera | Cheng Siu-keung | Director of Photography |
| Editing | David M. Richardson | Editor |
| Art | Jerome Fung | Art Direction |
| Crew | Wong Chi-Wai | Martial Arts Choreographer |
| Crew | Chi Shui-Tim | Pyrotechnician |
