The Two Faces of Evil plot
When the driver of a car stops to pick up a hitchhiker, he is attacked by the latter. A car accident ensues and the driver fights the insane man. He is seriously injured and is taken to the clinic. His wife learns that he sustained a throat injury during the fight and that he is unable to speak. She is asked to identify the attacker's body. It looks exactly like her husband and she begins to doubt which of the two is the killer. The only differences seem to be that the madman has rotten teeth and a claw-like fingernail. Who survived the battle - her husband or the madman?