Wales 1880: Young Tom Mortymer, son of rich industrialist Iestyn Mortymer, has turned his back on his inheritance for a gypsy existence with his young Romany wife, Jen Wildflower. In time, they come to settle on Flatholm Island where they run a refuge for animals. But their simple idyll does not last. They are aware of a strange malevolence towards them. One frightening incident follows another with relentless horror, until it is clear to Tom & Jen...