经过多年的追查，香港廉政公署准备对理达贸易集团负责人陈超群以及海关官员钟嘉玲（袁咏仪 饰）就非法内销行贿行为进行起诉。可是在开庭前夕，作为举报人和证人的理达的前任财务总监许植尧（张家辉 饰）临时改变出庭打算，启程前往澳洲。法庭给出七天限期，为此，该案负责人陈敬慈（刘青云 饰）和同在廉政公署供职的妻子江雪儿（林嘉欣 饰）联合展开调查。陈倾尽全力追查陈超群走私行贿的实证，并试图揪出其背后的大老虎。江雪儿则远赴澳洲，力劝许植尧回港作证。 　　短短的七天，一切争分夺秒，而在这一过程中，更多的真相交替浮现水面……The chief investigator of ICAC Chan King-chi (Sean Lau)'s childhood friend Hui Chik-yiu (Nick Cheung) does a spy job in the smuggler company even after he mysteriously fleets to Australia just before the summoned court appearance as a witness of the crime of the company. However, The chief investigator of ICAC Chan King-chi (Sean Lau) knows everything what Hui Chik-yiu does even after he fleets to Australia, and Chan King-chi's fatal mistake finally throws out everything ICAC team does during the most of the time in the film, and the mysterious manipulator kills corroborators of his coordinated crimes. Chan King-chi's mistake is that he does not officially record and register the spy Hui Chik-yiu. As the result, all proves and evidences are ineffective at court. It is fatally unintelligent and lack of professionalism, and it makes us not indulgent to the most of the time they spent in this film before the moment. Furthermore, ICAC is incapable to deal with the smuggling scheme and it ...