Alone in the world, Elspeth Swansome has taken the position of nanny to a family on the remote Scottish island of Skelthsea. Her charge, Mary, is a troubled child. Distracted and secretive, she hasn't uttered a word since the sudden death of her twin, William - just days after their former nanny disappeared. With Mary defiantly silent, Elspeth turns to the islanders. But no one will speak of what happened to William. Just as no one can explain the hypnotic lullabies sung in empty corridors. Nor the strange dolls that appear in abandoned rooms. Nor the faint whistling that comes in the night... As winter draws in and passage to the mainland becomes impossible, Elspeth finds herself trapped. But is this house haunted by the ghosts of the past?