****SPOILERS**** Michael "Iron Mike" Hammer, Stacey Keach, gives up on the law in busting this gang of professional hit-men called the "Prime Circle" in that the gang has intimidated everyone who comes in contact with it by not just murdering those witnesses but also police and even judges who dare to stand up against them. It's when investigative reporter Donna Hendrick was murdered by released cop killer due to lack of evidence, and no one willing to testify against him,Claud Fawner that Hammer being on the scene did the job, of shooting and arresting, on apprehending Fawner that the police and courts were not willing to do.
Not quite knowing what he's us against, the "Prime Circle", Hammer's testimony of seeing Fawner murder Donna Hendrick was thrown out of court on a technicality which caused Hammer to blow his top and almost have a contempt of court charge thrown against him. It's later that the "Prime Circle" try to whack Hammer but whack the wrong man Sammy, an old war buddy of his, who Hammer gave the key to his apartment that was blown up in a gas explosion, engineered by the "Prime Circle", for Sammy to sleep it off after getting drunk at a local bar.
***SPOILERS***Having to do the job that the police and courts won't Hammer went solo to track down not only the members of the "Prime Circle" but the person high up in the city D.A & Justice Department who's covering for them. In typical Mike Hammer style he ends up putting an end to the "Prime Circle" as well as Mister Big who in fact was hit by one of the killers that he was protecting-Claud Fewner-for refusing to give him a raise in his pay so he can check out of the country. As for Hammer himself he earlier almost got himself killed by not keeping his eyes off "The Face",Donna Denton, who so hypnotized him walking her poodles that he, by not paying any attention, was almost hit by a taxi running a red light.