On a foggy summer night, crime scene photographer Sarah Bain is called to the bank of the river Thames to photograph a murder victim, an unidentified woman whose face has been slashed. As Sarah takes photographs, she discovers that the woman is still alive. The case becomes a public sensation, and three parties quickly come forward to identify her. When the woman wakes and recognises one of the people, Sarah is delighted to reunite a family - until one of the claimants is murdered. Now Sarah is on the wrong side of the law and must find the killer before she finds herself headed for the gallows.