In a desolate Irish caravan, Mary struggles with her mysteriously troubled newborn, Síle. Her desperation leads her to Bridget, a mystic whose haunting revelation about a fairy changeling sets mother and child on a collision course with ancient folklore. As supernatural forces close in, Mary's maternal instincts clash with mounting evidence of the impossible. Her choices grow darker, and sanity blurs with superstition in this chilling exploration of motherhood's primal fears.