Simon Yam plays a triad boss in a family run business, who deals in arms. He has a good relationship with his sister, Amy (Suen Kin), until she finds out that her brother killed their father (Kenneth Tsang). Amy soon discovers that her brother is being watched by the police, and asks undercover cop Lilly (Emily Chu) to do all she can to arrest him. Lilly teams up with partner Alex Fong who go after the boss and his criminal friends.