*Fréwaka* contains almost everything you might reasonably order from the folk-horror catalogue: an isolated Irish village, an old woman barricaded behind iron, a fairy tree hung with offerings, hostile locals, a goat, Catholic iconography, inherited trauma and something ancient waiting for a family debt to be settled. The problem is not that the film lacks ideas. It is that it keeps putting them somewhere we cannot quite see them. Shoo arrives to care for Peig after the death of her own mother, and soon discovers a house organised around keeping something out. Iron objects guard doors and…