探讨人性的双面性，展示残忍、阴暗的另一个自己。布鲁克斯先生（凯文•科斯特纳Kevin Costner 饰）是个成功的上流社会人士，热衷慈善，德高望重，家庭美满。这样一个满分男人，人格里却有着另人不为所知的一面：另一个他自称马歇尔，不断诱使布鲁克斯以杀人为乐。他陶醉于连环杀人的乐趣中，就如染上毒瘾，却不料在杀害一名夫妇的时候，被一名摄影师拍下全过程。摄影师以此来要挟布鲁克斯，怎料却被布鲁克斯反攻一着。因为事情蹊跷，引来了女警探特蕾西的怀疑。于是布鲁克斯先生开始了他下一步的计划。Earl Brooks is a highly respected businessman and was recently named Portland's Man of the Year. He hides a terrible secret however: he is a serial killer known as the Thumbprint Killer. He has been attending AA meetings and has kept his addiction to killing under control for two years now but his alter ego, Marshall, has re-appeared and is pushing him to kill again. When he does kill a couple while they are making love, he is seen and photographed by someone who also has his own death and murder fetish. In a parallel story, the police detective investigating the murder is having problems of her own. She is going through a messy divorce and a violent criminal who had vowed revenge some years before has escaped from prison and is after her.