Retired hitwoman Wan is blackmailed into killing again or her cop son Joe will die. As witnesses and assassins are picked off in pairs, Joe investigates his mother’s past and a hidden mastermind.
| Actor | Role |
|---|---|
 Samuel LeongInspector Cheung | Inspector Cheung |
 Gregory Lee Wing-HoInspector Joe | Inspector Joe |
 Sidney YimJoe's mother / The Killer | Joe's mother / The Killer |
 Sophie Ngan Chin-ManMadam | Madam |
| NNg Yo-YoYoyo | Yoyo |
 Benny Lai Keung-KuenTerrorist | Terrorist |