To heal a broken family relationship, Adele (Maria Belo Maria Bello) and daughter Sarah (Sophie Starkey Sophie Stuckey) drive to Wales in search of their long-lost husband James (Sinn Bean Sean Bean). The natural scenery of the Welsh seaside eased the tense family relationship a little, but bad luck followed. One day, Sarah, playing by the sea, accidentally fell into the water. James and Adele immediately launched the rescue, but eventually found nothing, so Sarah disappeared from their lives. Immersed in great grief, Adele went through a series of strange things, believing that her daughter was trapped in the "dark world" of local legend. Adele sacrificed everything to get Sarah back. The film is based on Simon Maginn1997's best-selling thriller "Sheep".