Description
At Starliner Towers, a luxury apartment complex outside of Montreal, Dr. Emil Hobbes murders a young woman named Annabelle. He slices open her stomach, pours acid into the wound and then commits suicide. Nick Tudor, who has been suffering from stomach convulsions, finds their bodies but leaves without calling the police. The two bodies are found by resident doctor Roger St. Luc, who calls the police. Hobbes' medical partner, Rollo Linsky, tells St. Luc that he and Hobbes had been working on a project to create: "a parasite that can take over the function of a human organ".
After suffering more convulsions, Nick leaves work early. He vomits a parasite over the railing of his balcony. The parasite slithers back into the apartment, where it attacks a cleaning woman in the basement, attaching itself to her face. His wife Janine tries to care for him, but he ignores her and prefers to talk to the parasites undulating in his abdomen. At the clinic, Roger sees a sexually active middle-aged resident who has been suffering from stomach convulsions. Roger postulates that his condition might be an STD that he caught from Annabelle.
Linsky calls Roger from Hobbes' office downtown to tell him that Hobbes had developed a parasite that was "a combination of aphrodisiac and venereal disease that will, hopefully, turn the world into one mindless orgy". Hobbes believed modern humans had become over-intellectual and estranged from their primal impulses. Hobbes' ambition with his parasitic invention was to reassert humanity's unbridled, sexually aggressive instincts, and he used Annabelle as his guinea pig. Linsky warns Roger not to approach anyone who is behaving in a strange manner.
Nick tries to force Janine to have sex with him, but she recoils in horror when one of the parasites crawls from his mouth. She rushes to the apartment of her lesbian friend Betts, who was infected by one of the parasites while taking a bath. Betts seduces Janine and passes a parasite to her. Meanwhile, other residents become infected with the parasite, attack other residents and continue to spread the infection. Soon the hallways are full of people sexually assaulting or fighting one another. Roger combs the complex looking for the parasites while Forsythe, his nurse and lover, tends to an elderly couple who were attacked by one of the parasites.
Linsky arrives at Starliner Towers and goes to the Tudor apartment, as Roger had identified Nick as someone Annabelle might have infected. He finds Nick lying in bed, parasites crawling on his abdomen. When Linksy examines more closely, one of the parasites latches onto his cheek. Linsky tries to pull it off with pliers, but Nick kills him and swallows the parasite. Forsythe tries to flee the complex in her car but is attacked by the infected security guard. Before he can rape her, Roger arrives and kills him, and the two hide in the basement. Forsythe tells Roger of a dream that mixed eroticism and death, then vomits up a parasite. Roger knocks her out and tries to carry her to safety, but they are attacked by a horde of infected sex maniacs. Roger drops Forsythe to flee for his own safety, and she is overwhelmed by the infected. Roger kills Nick in his apartment, then tries to escape the complex via the swimming pool area. The infected block his path, and he is pulled into the pool by Janine and Betts. The rest of the infected hold Roger down while Forsythe infects him too.
Roger, Forsythe and the other Starlight residents drive out of the building's garage. Early the next morning, news reports encourage listeners not to panic as police investigate an epidemic of sexual assaults in Montreal.
After a scientist living in a posh apartment complex slaughters a teen girl and kills himself, investigators discover that the murderer had been carrying on experiments involving deadly parasites. Roger St. Luc (Paul Hampton), a doctor living in the building, and his aide, Nurse Forsythe (Lynn Lowry), then realize that the parasites are on the loose, attacking fellow tenants. And those who become hosts turn into erotically obsessed maniacs who pass the bugs on through violent sex.
