电影《保持沉默》讲述了著名歌星万文芳在密闭的化妆间遇刺，当时在场的只有吉米托马斯（孙睿饰）一个人。端木兰律师（周迅饰）作为吉米的辩护律师，准备为他做无罪辩护，因而在法庭上与该案的检控官吴正为（吴镇宇饰），展开了激烈的争辩，真相在一层层地被揭开。此时又有知情人称，嫌疑人吉米托马斯正是万文芳曾经遗弃的私生子，这个爆料也让案件的性质变成了“弑母”大案。随着本案的关键证人，万文芳的制作人田景程（祖峰饰）的介入，真相愈加扑朔迷离。Wenfang Wan was assassinated in Hong Kong in the dressing room. The investigation found that the suspect is a young man. Lawyer Lan DuanMu took over the case to start her investigation. During the investigation, she found that the prosecutor of the case was her former lover, Zhengwei Wu. At the same time, she found the case to have several doubts as she proceeded to seek the truth, and came to the Wan's home to for a final confrontation.