A virus has broken out across the Earth. People infected with it die and a turned into undead vampire like creatures.
Dr. Robert Morgan (Vincent Price) is the last human alive. He lives alone in a fortifed house and spends his days killing vampires and burning their bodies.
Morgan is immune against the virus but he is incredibly lonely. One day a dog appears but runs away from him. Later it appears wounded, infected by the virus. Morgan kills the dog with a stake and buries it.
Morgan sees a woman and convinces her to return to his place with him. She informs him that she belongs to a group of people who use a vaccine to control the virus. Morgan doesn’t trust her.
Based on Richard Matheson’s I Am Legend this first adaptation is the most faithful and Matheson himself wrote the screenplay but he removed his name from the film when he became dissatisfied with the movie.