In the California desert, cult leader Thomas Reanhauer meets his disciple, “Brother” Stevens to discuss the recent death of fellow disciple, William Mims. When Reanhauer convinced William to stop taking insulin for diabetes, the man died, and Stevens fears the authorities will come after the cult. Reanhauer believes he has the power to bring William back to life, although he has been dead for weeks. Reanhauer and a group of disciples attempt to “raise” William in a ceremony, but Reanhauer falls over from a heart attack. Rushed to a Los Angeles hospital, he later dies during surgery under the care of Dr. Peter Desmond and Dr. Nelson. Nurse Sherri Martin, also present in the operating room, senses a strange presence at the moment of Reanhauer’s death. After the surgery, Peter and Sherrie share a kiss and make a date. In the hallway, fellow nurse Tara Williams excitedly tells Sherri that professional football player, Marcus Washington, has become a patient. Tara visits his room, claiming to be a fan, but Marcus has been recently blinded from a car accident and demands that she leave him alone. That evening, at Sherri’s apartment, an evil spirit possesses her as she sleeps. The next day, at the hospital, Marcus apologizes to Tara and they discuss his career, but Marcus becomes depressed, realizing his glory days have ended. Later, Peter invites Sherri, Tara, and fellow nurse Beth Dillon to lunch, but Sherri skips the gathering to drive to a cemetery. Meanwhile, at Stevens’ apartment, items in the room move of their own accord. When a knife flies toward Stevens and lands near his head, he hears a nefarious laugh and believes it is Reanhauer’s evil spirit. Later, at the hospital, Peter asks Sherri where she disappeared to during lunch and she claims the event slipped her mind. Later, Sherri sneaks into Marcus’ room in a possessed state, but freezes at the sight of a unique bracelet on his arm. Feeling a chill, but unable to see, Marcus asks who is there, but Sherri leaves. Sometime later, Peter asks Beth if Sherri is seeing another man, and Beth reassures him that Sherri is devoted. Meanwhile, Tara visits a shaken Marcus, who reports feeling a cold, evil presence in his room earlier, but Tara suggests his medications are provoking hallucinations. The next day, Sherri drives to Dr. Nelson’s farm, pretending to deliver a package, then stabs him with his own pitchfork. She returns to the hospital in a daze and wanders into the locker room with blood on her face and hands, frightening Tara. That evening, at Sherri’s apartment, Peter questions her about the incident, and she responds in a possessed voice, warning Peter not to interfere. The next day, Peter visits a psychiatrist friend to discuss Sherri. He remembers that Sherri uttered something that mirrored a phrase Reanhauer said before he died. Reanhauer had refused medical treatment from Peter, claiming that science was a “finite power.” Diagnosing Reanhauer mentally ill, the doctors dismissed his wishes and operated on him anyway. Sherri was present when Reanhauer died. The psychiatrist suggests that Reanhauer might have indoctrinated Sherri with his beliefs, and Peter agrees to look into the matter. In the parking garage, an intoxicated Stevens accosts Peter, demanding to know Reanhauer’s burial place. Peter tells him to come back to the hospital when he is sober and leaves. Undaunted, Stevens chases Peter in his car. Taunted by Reanhauer’s spirit, he loses control of the vehicle. Stevens jumps out before the car careens over a cliff. Back at the hospital, Tara asks about Marcus’s bracelet, and he explains it is a present from his Haitian voodoo priestess grandmother, designed to ward off demons. Marcus gives Tara the bracelet. Meanwhile, at Sherri’s apartment, Peter asks about her interaction with Reanhauer and she recalls him declaring her one of the chosen few; Reanhauer wanted to introduce her to the “bliss that lies beyond the borders of hell.” Back at the hospital, Peter questions Beth about Sherri. Beth recalls that Reanhauer constantly spoke of the devil, and was fond of Sherri. That night, Sherrie returns to the hospital, stabs Dr. Brown, then goes to Marcus’ room. Speaking in the voice of Marcus’ dead grandmother, Sherri announces that she wants him to join her in hell. Before Sherri can stab Marcus, Tara enters the room and Sherri freezes in the presence of the protective bracelet. Peter runs in as Sherri, speaking in Reanhauer’s voice, proclaims he will kill everyone responsible for his death. On the other side of town, Stevens breaks into the Los Angeles County hall of records. Intoxicated, he searches for Reanhauer’s burial site, but takes an incorrect record. He then exhumes the wrong body and throws the corpse into a factory furnace. Reanhauer appears, laughing at Stevens’ mistake. Stevens panics and falls into the furnace, burning to death. Elsewhere, Peter argues with the psychiatrist about committing Sherrie to a mental institution. Peter does not trust sanitariums and hires psychiatric Nurse Gordon to take care of Sherri at her apartment. Back at Marcus’ hospital room, Tara and Beth learn of the Haitian ceremony to rid Sherri of her possession. They must find the grave of the demon and burn all corporeal remains. Marcus explains that Sherri has no knowledge or control over what she is doing; once the demon is exorcised, she will return to normal. Beth suggests using hospital records to find Reanhauer’s grave. That evening, Tara and Beth go to the cemetery, while Peter check in on Sherri. Finding Nurse Gordon dead behind the couch, Peter searches for Sherri as Tara and Beth exhume Reanhauer’s corpse. Just as Sherri jumps out of her apartment bathroom, wielding two knives, Tara and Beth set fire to Reanhauer’s remains. Sherri drops the knives and faints. The next day, at the hospital, Marcus, Peter, Tara and Beth explain that Sherri was possessed, but the psychiatrist does not believe them and recommends that Sherri be institutionalized.