In St. Marks catholic boarding school for girls, the religious student Elizabeth is attacked by evil forces and disappears from the classroom and the impotent Father Drake is incapable of saving her. The school is closed and five years later it is reopened. Five troubled unwanted girls - Alex, Mara, the blind Cecilia, Leah and Connie - are left by their family in the institution, severely directed by the headmistress Miss Pearce with hands of iron. Father Drake is their teacher and the girls are forbidden to go to the mysterious third floor. When Alex has visions of the possessed Elizabeth, weird things happen in the spot and the girls have to fight against a legion of two thousand demons.

While filming a horror movie of mummy in a forest, the students and their professor of the University of Pittsburgh hear on the TV the news that the dead are awaking and walking. Ridley and Francine decide to leave the group, while Jason heads to the dormitory of his girlfriend Debra Monahan. She does not succeed in contacting her family and they travel in Mary's van to the house of Debra's parents in Scranton, Pennsylvania. While driving her van, Mary sees a car accident and runs over a highway patrolman and three other zombies trying to escape from them. Later the religious Mary is depressed, questioning whether the victims where really dead, and tries to commit suicide, shooting herself with a pistol. Her friends take her to a hospital where they realize that the dead are indeed awaking and walking and they need to fight to survive while traveling to Debra's parents house.