Which witch?

Miles away from town or city, and centuries away from civilization, three witches dance around a great brass cauldron, singing songs of horror and hatred. The Crone raises her voice to ask: 'When shall we three meet again?'... only for the cauldron to emit a thick, poisonous smoke, sending her, and her fellow actresses, fleeing for their lives. For the director, it's the last straw. Macbeth is famously a cursed play, but the incident, not the first in a long line of creepy events, makes him wonder if someone - or something - is trying to sabotage the play. The show must go on! But not if the forces of darkness are determined for it not to. Talented actress Diana Hunt, hired to give her Lady Macbeth, knows just the man to turn to for help: her partner in crime-solving, handsome young bishop Alistair Kincaid, whose help investigating a series of seemingly supernatural murders has earned them the nickname the Holy Terrors. But with evil and black magic wrapping the theatre in darkness, this investigation might cost Alistair and Diana far more than they're expecting.