In 1945, Grace Stewart (Kidman) and her two children live an unusually isolated existence in a secluded mansion on one of the Channel Islands. The arrival of mysterious new servants (Fionnula Flanagan, Ed Sykes) and her apparently war-fatigued husband Charles (Christopher Eccleston), raise the unworldly feeling that there is far more to this house than can be seen, provoking Grace into a terrifying fight to save her children and preserve her sanity.