Banker Fung Yan-tsang is a seasoned criminal in fraudulent activities. The righteous cat burglar Ham Siu-fo has issued a deadline for Fung to return the scammed money. Despite the obstacles put up by Fung's allies Chow Wai-pak and his stepwife Julie, Ham still manages to reclaim the money which is accordingly returned to the customers. In the process, Ham is reunited with her long-lost twin sister Katherine, Chow's daughter. Since losing her mother whose health took a turn for the worse after Chow's marriage to Julie, Ham has undertaken a chivalrous course in the footsteps of her aunt. She thwarts the scam marriage set up by Fung for Katherine and his idle son, using the servant Chu Yat-keung as bait, and exposes Fung's illicit affair with Julie. Crossing boundaries of class and wealth, the servant Chu and Katherine become man and wife. A happy Ham leaves, continuing to devote her life to the causes of social justice.