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.

    Chuck Norris plays a tough, honest, Chicago cop. He gets trapped in the middle of an Italian-American mob war and tries to rescue an innocent kidnap victim. An underlying plot is Norris bucking the department over a questionable shooting of an Italian-American kid by a veteran cop. The only witness is a young police officer.

    Eddie Cusack is an honest cop, who was conducting an operation involving some Columbian drug dealers. Now someone attacks the Columbians, killing all of them, and in the melee, one of the cops shoots a boy. He then proceeds to plant a gun on the boy. Now the brother of the Columbians, wants revenge on the one who did this. It turns out that the one responsible is the relative of a local mobster, he runs away when the retaliation starts. Most of his family was killed except for one daughter who doesn't exactly like what her father does. Cusack manages to save her and gives her some protection. Now the cop who shot the boy is given a hearing to determine if he was responsible. At the hearing Cusack denounces him. He then learns that the girl's been grabbed by the Columbian, he goes to help her but no one in the police department is willing to help him. He has to help her own his own.

    Eddie Cusack is a tough Chicago policeman facing two crises stemming from a bloodily botched narcotics sting. The first involves a war that ensues between the gang of Tony Luna and Felix Scalese against Columbian "businessman" Luis Comacho, a war that sweeps up Tony Luna's daughter. The second involves Cusack's new partner, Kopalas; during the botched sting Kopalas witnessed another cop, a burned-out alcoholic named Craigie, shoot and kill an innocent youth then plant a gun on the youth, and Kopalas is torn because he fears breaking the code of silence that exists among his fellow Chicago cops - a code of silence that sweeps up Cusack when, at a civilian review board he testifies against Craigie, and is abandoned by his fellow cops when Luna's daughter is kidnapped by Comacho, Cusack is badly beaten by Comacho's gang, and Cusack must settle the gang war (and rescue the girl) once and for all with a "borrowed" robot police tank.