秘密三女探
The Flying Dragon gang goes on a rampage and the police Inspector is at his wits' end. He then commissions Wong Ngung, Wu Ngar and Heung Nga to help him catch the gang members. Suet-ying, a young woman, is addicted to gambling and owes a huge sum to the gambling den that belongs to the Flying Dragon gang. She has even signed IOUs. When the younger sister of Ying's husband sees that Ying is weighed down by worries, she asks Wu Ngar for help. Wu Ngar sneaks into the gambling den, but her behaviour is suspected by the gang leaders, Tai-kit and Tai-hong. Fortunately, Wong Ngung saves her. To get back the IOUs, Ying falls under the control of Hong and Kit. Master Lung has evil designs on Ying. He first kills Kit and seizes Ying. Hong then shoots and kills Lung. Wong Ngung and her two partners get back the IOUs for Ying. They notify the police Inspector to arrest the members of the Flying Dragon gang. Hong is shot and injured by Wong Ngung. He is arrested with the other gang members.
