Allison wakes up one morning believing she is Sandra O'Bannon. She obviously knows a great deal about the woman - where she lives, the location of the spare key and the access code to the house. She dreams that she and her husband, Tom O'Bannon, are in a car accident and subsequently meets Tom and Sandra at a hospital finally realizing that something is very wrong. Her dreams however provide an explanation to what happened to the real Sandra O'Bannon.
—garykmcd