Adele (Maria Bello) and her young daughter visit the child’s estranged father (Sean Bean) on the Welsh coast. But relations between mother and child are strained, and before long the kid goes missing, presumed drowned. So who’s the other girl who appears in her place? Is it really the daughter of the former landowner, the mystic who engineered the mass suicide of his brethren? And while we’re at it, what’s in the box Adele finds in the attic?