1992年4月的洛杉矶, 种族气氛非常浓烈。当时有一个曾经引起市民震惊全美的大骚乱的案件：4个白人警官殴打黑人而被判无罪。本片正是讲述宣判前几天警署里面发生的事情。 洛杉矶警局精锐的特别调查小队接受了一个倍受关注的4条人命案。其间警探艾尔顿•佩里(库尔特•拉塞尔Kurt Russell 饰)向新人鲍比•泰德鲁(斯科特•斯比德曼Scott Speedman 饰)讲述差馆种种腐败、阴暗的现象；而黑人警官豪岚(文•雷姆斯Ving Rhames 饰)亦对警署极为不满，决心追查到底。就这样，几个警员在腐败丛生的环境中，坚守着良心和正义。影片揭露了当时洛杉矶警署内部贪污、勒索、酷刑等内幕，这些错综复杂的因素最终引发了全美震惊的市民暴乱。
Plot Summary:Set in the Los Angeles Police Department in April 1992, Dark Blue is a dramatic thriller that takes place just days before the acquittal of four white officers in the beating of black motorist Rodney King and the subsequent L.A. riots. In this racially-charged climate,the LAPD's elite Special Investigations Squad (SIS) is assigned a high-profile quadruple homicide. As they work the case, veteran detective Eldon Perry, known for his tough street tactics and fiery temper, tutors SIS rookie Bobby Keough in the grim realities of police intimidation and corruption. Meanwhile, Assistant Chief Holland, the only man in the department willing to stand up to the SIS, threatens to end Perry's brand of singlehanded "justice" on the Los Angeles streets. While navigating through the tumultuous neighborhoods of South Central L.A., Perry and Keough must track down cold-blooded killers and face their own demons, which prove to be more ruthless than the criminals they pursue.
