Bryan Morgan, Bill Condon the mayor’s son in Galesburg, Illinois, is brutally murdered in his own home, and his body is later found stuffed and posed as a scarecrow, a grotesque image that unsettles the town and prompts a relentless investigation. Local John Brady, Michael Murphy, a seasoned police investigator, dives into the case, tracing a trail of violence that seems to echo a disturbing pattern. As the case unfolds, Pete Brady, Dan Shor, a high school senior, sits in on a course at Galesburg University with his friend Oliver Myerhoff and becomes entangled in a web of experiments, loyalties, and hidden motives.
During the course, Gwen Parkinson, Fiona Lewis the professor of the class, screens a lecture by her late mentor, Dr. Le Sange, whose influence reaches back to Pete’s mother, Catherine, who once worked for him. After the lecture, Pete volunteers to become one of Gwen’s test subjects, hoping the stipend will pad his college applications and open doors for his future. The narrative then shifts to a lively house party, where the mood shifts from carefree to terrifying: Waldo is stabbed to death outside by a masked assailant, and Waldo’s girlfriend Lucy, Elizabeth Cheshire, is attacked and nearly drowns in the pool. Pete and others rush to rescue her, and the masked figure flees, unmasked in the distance as Oliver, the very friend they had been with earlier that night.
John Brady questions Oliver, who admits he cannot recall the party’s events, claiming he was drunk. The investigation deepens as medical examiners note Waldo’s corpse bears a bizarre surgical incision near the eye, suggesting that two different assailants are responsible for the murders of Waldo and Bryan. Meanwhile, Pete returns to Gwen’s laboratory, a sprawling facility that conducts both human and animal experiments. Gwen subjects Pete to a mind-bending session: he swallows a pill, repeats a string of words, and is then dismissed. Pete begins a tentative romance with Caroline, a college student who works at the lab’s front desk, and what starts as a practical arrangement grows into something warmer and more complicated. Caroline, Dey Young, becomes a confidant as the body count rises.
The following day, a woman reports her son Timothy, Neil McLachlan, being dismembered in his bathroom by an unknown young woman; the distraught mother calls the police before being stabbed herself, and she manages to convey a few details to her friend Mildred before meeting a brutal end. The investigation pressures Gwen, and John suspects that a female subject from Gwen’s program might be involved. He confronts Gwen at the lab, unaware that Pete is in one of the test rooms, restrained in a chair. After John leaves, Gwen resumes the session and injects Pete with another substance, pushing him toward her control.
Back at the home front, Pete joins Caroline for dinner, but begins to deteriorate, vomiting blood and growing dangerously ill. John talks with his girlfriend, Barbara Moorehead, Louise Fletcher, about the murders, piecing together that each victim is the son of a man who once collaborated with John to expose Le Sange’s unethical experiments, and he comes to fear that Le Sange might still be alive and seeking revenge. Barbara follows John to the cemetery, where he breaks into Le Sange’s crypt and finds only two skeletonized lower legs—an ominous sign that their target may be on the loose.
John and Barbara return home to find a dazed Pete and Caroline waiting. A shotgun in hand, John heads toward the university, while Barbara recounts how Pete’s mother, Catherine, behaved oddly during her employment under Le Sange, and how her death remains unexplained. Pete and Caroline decide to tail John to the campus, where a chilling scene unfolds: Pete enters a chamber where John is communicating with Gwen via a small screen. Gwen’s mind-control methods enthrall Pete, who is ordered to seize his father’s gun. A legless, wheelchair-bound elderly man—revealed to be Le Sange in disguise—enters and proclaims a grand, if warped, philosophy of control and order. In a fraught confrontation, Le Sange instructs Pete to slash his wrists, and then to stab his own father to death. Pete, driven to a breaking point, declares that he “is his father” as the truth about Catherine’s affair with Le Sange comes to light, revealing that John is not Pete’s biological father. In a final, tense moment, the police intervene and Gwen is arrested.
In the aftermath, with the sinister apparatus dismantled, life begins to heal. A recovered Pete, standing on the threshold of adulthood, attends his father’s wedding to Barbara, accompanied by Caroline, signaling a fragile but hopeful possibility of normalcy returning to a town scarred by manipulation, betrayal, and fear.
