Robert Bridge is a psychology lecturer and specialist in the study of psychic mediums. Though deeply sceptical of psychics and their abilities, Robert takes his students to an 'evening of clairvoyance' where he meets Alison Mundy. Reluctant and troubled, she is a far cry from the fraudulent psychics that Robert is used to. Ever since she was a child she has seen spirits, and after a near death experience they are beginning to take over her life. She has moved to Bristol in an attempt to start afresh, but it hasn't worked and as she lies awake at night she can't escape the voices that cry out to her. When Alison's readings provoke an adverse reaction in one of Robert's students he begins to study her with the intention of writing a book about her. But Robert is completely thrown when Alison claims to the see the spirit of his own dead son Josh who was killed in a car accident two years earlier.