Lancaster plays an ex-Chicago policeman, Jim Slade, who has just been released on parole from prison for shooting his wife's lover in their bed. He goes to live with friends, played by Cameron Mitchell and Joan Lorring, in a small town where he has been offered a job (part of his parole agreement) as a night watchman at the local Jordan College, the campus of which is portrayed by Clemson University. A coed is murdered (Catherine Bach) and the local sheriff (Harris Yulin) tries to pin the crime on a creepy college janitor who spouts Biblical revelation while hiding pornography, played by Charles Tyner, who would be cast a year later as the pyromaniac murderer in The Longest Yard. Slade has other ideas and pursues an unauthorized investigation of his own. "Taking the lid off the hornet's nest involves him in considerable danger as blackmails, beatings, attempted rape and further murders wrestle for screentime before the long and-overcomplicated drama grinds to a close."
The murdered student turns out to be the daughter of Senator Clayborne (Morgan Woodward), who is subsequently receives blackmail letters over his daughter Natalie's confession to her campus psychiatric department counselor about an incestuous relationship with her father. Incriminating cassette tapes of the account have fallen into the hands of the blackmailers. Slade questions various possible suspects including Natalie Clayborne's estranged boyfriend King, (played by Burt Lancaster's son, William), who declares to Slade that the generation gap "just got a little wider", Dean Collins, the psych professor, ( played by actual Clemson faculty member Harold N. Cooledge Jr.), a nerdy student whose taped psych rant was also stolen, and Senator Clayborne.
All the while, Slade is being warned off of overstepping his authority as a mere night watchman, no longer a cop, by his parole officer Linda Thorpe, played by Susan Clark, as well as by his buddy Quartz, played by Mitchell. Lancaster has a brief affair with Clark. A rustic family of thugs overseen by a "Ma Barker"-ish mother provide misdirection in the plot, as well as turning out to be "muscle" for certain corrupt members of the Sheriff's Department. Their appearance on screen is always accompanied by a hwonking harmonica to emphasize their hillbilly status. Ed Lauter portrayed one of the sons.
The story concludes with Jim Slade realizing that both the parole officer and his buddy Quartz are the powers behind the crime, a conclusion that has to be narrated for the audience in a "thought" monologue by Lancaster as he watches his friend hobble around the cinder track of historic Riggs Field at Clemson, on crutches from a broken leg suffered early in the film. Only Quartz could have known one critical clue in the cover-up of the original murder. Sheriff Casey rolls up and arrests Quartz. Slade confronts Thorpe, who produces the stolen tapes, hidden in her freezer, knowing that the jig is up and she is about to be arrested.
The film concludes with the sheriff offering Slade an apology, and a job. This is one of the major flaws in the film since, as a convicted violent felon, Slade cannot hold a position in law enforcement or carry a firearm. Roll credits.