Rafael / Father Damon, John Holland, a Roman Catholic priest, murders a man outside a castle-like estate on an island in upstate New York. The victim claims to be Lucifer himself, and promises to return. Decades later, in 1963, Andrew Williams, [Stefan Arngrim], is born. After his mother is paralyzed under mysterious circumstances, Andrew's father realizes something peculiar about his son, eventually coming to the realization that Andrew is the son of Lucifer.
In 1980, as a senior in high school, Andrew is academically brilliant, but withdrawn and socially awkward. Consequently, he is often bullied by his peers. Andrew feels drawn to the estate where Father Damon committed the murder, which is due for demolition for an impending golf course.
At school one day, one of Andrew's tormentors, Tony, attempts to harass him in the gym shower. Overcome by strange powers, Tony kisses him in front of their peers. The event leaves Tony hysterical, and he leaves, terrified of Andrew. Later, Andrew is notified that he has received scholarships to several Ivy League colleges, including Yale and Harvard, but is indifferent to the news.
Meanwhile, a local elderly woman, Margaret, visits Father Daly at his parish, and discusses Damon, whom she knew personally; Father Daly insists Damon wrongly murdered the man, though Margaret believes he was in fact Lucifer, and Father Daly, a manifestation of the archangel Raphael. One of Margaret's few friends is actually Andrew's father, the local mailman, who always talks to her when he makes his deliveries. He insists that Father Damon was a good man and a good priest, and that the town did him a disservice by convicting him.
During a gym class, one of Andrew's classmates, Mark, inexplicably suffers ruptured organs during a dodgeball game and dies. Mark's girlfriend, Julie, is distraught, and shortly after begins having bizarre visions of Andrew raping her. She later hears voices calling her Gabrielle (a feminization of archangel Gabriel), and is directed to Margaret's home by the disembodied voice of Father Damon. Margaret appoints Julie her protégé to battle Andrew.
On the night of a school dance, Andrew arrives at the castle estate and invokes Leviathan and Beelzebub, and summons the undead from grave sites on the property. At a local bar, Andrew's father drunkenly raves about his son being the devil before returning home and shooting his wife in the head. Simultaneously, a group from the school is showing an outdoor play retelling the life of Jesus. During the scene of the crucifixion, the actor onstage playing Jesus begins exhibiting real stigmata, causing the audience to flee in horror.
On the island, a group of teenagers arrive to party after the dance, including Tony, his girlfriend Marie, Brenda, and others. After arriving at the castle, they are accosted by the undead. Marie is killed, and Tony and Brenda flee to an upstairs room, where Tony finds he has inexplicably developed breasts. Andrew enters the room and kisses him, after which Tony stabs himself to death to avoid getting raped. Andrew carries Brenda outside and lays her on an altar, where he stabs her to death.
Margaret and Julie arrive on the scene, brandishing Father Damon's processional cross, which causes Andrew to recoil. Margaret forces Andrew to recite the Lord's Prayer, and he transforms into Mark, tricking Julie. Margaret intervenes, and he kills her by breaking her neck. Julie watches as Andrew transforms into Lucifer, but is able to defeat him with the power of Father Damon's crucifix. The spirits of Julie, Father Damon, and Margaret—the three archangels—coalesce, as Andrew is engulfed and destroyed in a beam of a light.
