A young woman, Zoey, finds herself in a hospital room in an underground fallout shelter. The doctor, who runs the shelter, explains that an infection has killed the entire population above ground. The only people left are either a few lone survivors like herself, and the infected... the living dead. The only way of curing the infection, she is told, is by surgically removing the affected area. The doctor is assisted by a nurse who has seemingly gone completely insane. Together, they "treat" a steady stream of survivors. The doctor wants Zoey to to replace the unstable nurse and become his new assistant. Zoey is very hesitant, but the doctor is willing to do whatever it takes to survive, no matter how questionable or terrible the acts. But after a patient offers to trade places with Zoey and do "anything" the doctor wants, Zoey realizes that if she doesn't do these terrible things, someone else will do these things to her. Zoey has to decide what she is willing to do to survive, and ...