An American college student in Rome and his sister in New York investigate a series of killings in both locations where their resident addresses are the domain of two covens of witches.

[Reading from "The Three Mothers", by E. Varelli]
Rose Elliot: I do not know what price I shall have to pay for breaking what we alchemists call Silentium, the life experiences of our colleagues should warn us not to upset laymen by imposing our knowledge upon them.
Mark Elliot: She writes poetry.
Nurse: A pastime especially suited for women.
Kazanian: There are mysterious parts in that book, but the only true mystery is that our very lives are governed by dead people.
Sara: Have you ever heard of the Three Sisters?
Carlo: You mean those black singers?
Sara: No, I'm talking about mythology.
Carlo: Hold on, if you're talking about spooks and stuff, I don't believe in any of that.
Sara: How can you be so sure?
Carlo: I don't believe in such things, that's all, and without any philosophical discussion.
Sara: Then what do you believe in?
Carlo: In whatever I can see and touch.
Sara: May I ask a strange question?
Mark Elliot: How strange?