What secular terrors lurk behind the walls of a secret Irish convent? Northern Ireland, 1960: Father Thomas Riley (Lalor Roddy) and Father John Thornton (Ciaran Flynn) are sent by the Vatican to investigate the reports of a miracle - a statue of the Virgin Mary crying blood - in a remote Catholic asylum for "immoral" women. Armed with 16mm cameras to record their findings, the priests instead discover a spectacle of depraved horror of sadistic nuns, Satanism and demonic possession.