Overheard (竊聽風雲) is a 2009 Hong Kong crime thriller film written and directed by Alan Mak and Felix Chong, and produced by Henry Fong and Derek Yee.
A major stock exchange in the world, Hong Kong attracts not only money but any who try to manipulate the market. At the Hong Kong Police Force Commercial Crime Bureau, an operation is underway to infiltrate a trading company, Feng Hua International where a man, nicknamed "Boss" is the chief suspect. The team of Criminal Intelligence Bureau officers, led by Inspector Leung together with Yeung and Lam , installs interception devices to monitor the company's communications. Yeung is a family man, has a wife, a daughter, and a son who is suffering from a serious illness and needs constant attention, while Lam, a young new comer to the team, is to be married to the daughter of a wealthy man. Leung is a calm experienced officer who is having an affair with Mandy who happens to be the wife of his friend Lee.
Lam sniffed a weird message from the gang but failed to crack the secret. As he realized that he was in risk, he hid the record behind a movie poster. Can you uncover the secret?