When a charming 12-year-old girl takes on the characteristics and voices of others, doctors say there is nothing they can do. As people begin to die, the girl's mother realizes her daughter has been possessed by the devil - and that her daughter's only possible hope lies with two priests and the ancient rite of demonic exorcism.

Follow the lives of two very different priests tackling one family’s case of terrifying demonic possession.

A young couple, Rosemary and Guy, moves into an infamous New York apartment building, known by frightening legends and mysterious events, with the purpose of starting a family.

Young Rosemary Woodhouse and her husband Guy move in with a rich couple, who soon take an unusual interest in the Woodhouses' attempts to have a second baby after Rosemary miscarried the first one. Guy soon has unusual success and Rosemary becomes pregnant, but it becomes clear that the two are connected and that the pregnancy may not be all that Rosemary hoped for...