Yim Tai-hung stages a diamond heist but one of his men slips away with a diamond necklace. Sustaining a fatal wound, the betrayer gives the necklace to his friend Chow Ping at Rose Apartment before he expires. Chow calls her cousin Wu Nga for help. But Wu, Wong Ang and Heung At come too late. She however manages to reveal the whereabouts of the necklace at her last breath. The trio is framed for the murder but is later acquitted. Striving to crack the case, Wong infiltrates the apartment at night and uncovers the necklace, which is then used to lure the real culprit out. But her plan is foiled by a young and reckless Wu who falls into Yim's trap. Luckily Wong and Heung deliver the hostage to safety while the police arrest Yim's accomplices and kill the ringleader in the ensuing shootout.