A family of cityfolk suffer a hostile reception from locals when they relocate to an isolated old house deep in an ancient Irish forest. So far, so generic. But the locals in this sporadically impressive first feature from Corin Hardy are malicious magical entities – fairies and wood nymphs banished by humanity centuries ago, and still nurturing a grudge. These are no gossamer-winged sylphs, however, but gnarled hobgoblins with decidedly bad intentions and a symbiotic relationship with a particularly grisly neuro-active fungus. Anyone squeamish about eye trauma should approach with caution.

The production design evokes the baroque organic menace of Guillermo del Toro’s enchanted otherworlds; the inventive sound design uses the high-pitched electronic whine of a charging camera flash to unsettling effect. The film is most effective when it explores the idea of crass environmental insensitivity and nature’s revenge. It is least successful when it descends into a routine baby-in-peril story.