Suppose you were an up-to-date young wife who moved into an old and elegant New York apartment house with a rather strange past. Suppose that only after you became pregnant did you begin to suspect the building harbored a diabolically evil group of devil worshippers who had mastered the arts of black magic and witchcraft. Suppose that this satanic conspiracy set out to claim not only your husband but your baby. Well, that's what happened to Rosemary... Or did it...?