Three days after Christmas, a woman walks into a police station. She has no phone and no ID, just a piece of paper with the name of missing persons investigator David Raker on it. She tells officers that Raker is her husband. When he turns up at the station, Raker is stunned. The woman looks exactly like his wife. She knows all about their marriage, their history, even private conversations the two of them had. There's just one problem: Raker's wife...