Mainland assassin Yin Ying, otherwise known as Cat (Almen Wong) carries out a series of hits on local triad bosses. Senior cop John Cannon (Michael Wong), investigates the aftermath of each crime and soon picks up her trail. Aware that she is being tailed, Cat turns the tables and follows him around. Eventually, the hunter becomes the hunted and two find themselves in a relationship, enabling them to take on what ails them as a team.