Rose (Marilyn Chambers) and her boyfriend Hart (Frank Moore) are out driving along the road on his motorcycle when they crash because a car has broken down on the road. Hart is fine but Rose is badly injured in the crash and badly burned.
Rose is taken to the Keloid Clinic for Plastic Surgery where Dr. Dan Keloid (Howard Ryshpan) decides to try a new procedure on Rose to graft new skin on her damaged body. Rose is in a coma for a month after the procedure when she finally comes to. She appears normal but something has changed. The procedure has altered Rose. She now needs blood to survive.
Because Rose needs blood her body has developed a stinger that comes out of her armpit to help her feed on people. There is also a very bad side effect for her victims. They become almost like zombies except they foam at the mouth and start attacking other people infecting them too. Rose infects a patient who gets out into the city and starts infecting others while she ends up also feeding and infecting Dr. Keloid. She soon escapes the hospital.
Before you know it a pandemic has broken out in Montreal with the infected causing chaos in the city. Rose goes to a friend’s apartment while her boyfriend Hart desperately tries to find Rose. Things start getting out of hand as martial law is declared in the city.
This was David Cronenberg second feature and it has similar themes to his first feature Shivers. Cronenberg originally wanted Sissy Spacek but the producers decided on Marilyn Chambers because while she wanted to break into mainstream movies, they wanted someone who help sell the low budget film to other countries.