A woman is attacked by a vicious serial killer and survives, but she is unable to identify him because she suffers from prosopagnosia, or 'face-blindness', the inability to recognize faces and facial features. Any person in her life, even friends or family, could possibly be the killer, but she is unable to tell which one because they look different to her every time she sees them. As she struggles with her problem, the killer could strike again at any time.