查克·诺里斯饰演一名正直的芝加哥警探艾迪，却夹在贪污的警察局同僚和当地的义裔帮派之中，使他变成一个我行我素的独行侠。在一次监视黑帮火并的过程中，艾迪因故未能赶抵现场，导致无辜者惨死，并且有人遭黑帮绑架，他必须尽力将歹徒的行踪调查清楚并救出无辜。另一方面，局中有贪污同僚滥杀义裔小孩被另一年轻警员看到，但他却不敢说出真相。于是艾迪在消灭黑帮之余，还要分心对付自己人。Eddie Cusack is a Chicago police officer about to bust some members of the Comacho gang when the gang is shot up by a rival drug gang from the neighboring building, led by Tony Luna. Victor Comacho is the only survivor of the Comacho gang and his older brother, Luis, who is the leader of the gang, retaliates by killing Luna's family and kidnaps Luna's daughter, Diana. Cusack must face Tony Luna and Luis Comacho alone because nobody on the police force is willing to help him since he was the only cop who broke the code of silence by testifying against a fellow cop who killed an unarmed teenager, but Cusack is not really alone. A police robot called "Prowler" aides Cusack as he takes down the gangs.
