Successful young sculptress Kate Dawlish is talented and troubled. The blackout comes out of nowhere and when she wakes up on the floor of her Exeter studio, she finds a stranger helping her. He tells her his name is Tom. He says he's her fiancé. As Kate recovers with Tom's help, memories return but something is still wrong. She's hearing voices. A stranger in a fedora hat is following her. When she takes Tom to the family home in Cornwall to meet her eccentric mother, Verity implies that Kate killed her stepfather, John Dawlin. She says Kate's relationship with John was unhealthy. Kate escapes with Tom to the beach house, where he finds old photos of her stepfather with another woman and a baby. When Kate returns to Exeter she discovers that twin sister Angie is seeing her neurologist Nick Siegel, and sharing secrets. Nick warns Kate that she may be psychotic. Three weeks before the wedding, Kate meets her stepfather in an Essex market and he tells her that he's coming back. Two weeks before the wedding, there's a violent confrontation at the family home and John dies. She disposes of the body in a cave below the house. One week before the wedding, the man in the fedora forces his way into her studio and stabs her to death... Only Kate isn't dead and the nightmare is only just beginning.