In response to a global rise in demonic possessions, the Catholic Church reopens exorcism schools to train priests in the Rite of Exorcism. On this spiritual battlefield, an unlikely warrior rises: a young nun, Sister Ann. Thrust onto the spiritual frontline with fellow student Father Dante, Sister Ann finds herself in a battle for the soul of a young girl and soon realizes the Devil has her right where he wants her.

Biochemist Michael Morbius tries to cure himself of a rare blood disease, but he inadvertently infects himself with a form of vampirism instead.