In a post-epidemic nightmare world, scientist Robert Morgan (Vincent Price) is the only man immune to the plague which has transformed the entire population of the Earth into vampire-like creatures. He becomes the monster slayer that vampire-society fears.
Curing one of them, Ruth (Franca Bettoja), with a transfusion of his blood gives him hope for the future. It is a short future, however, since the other vampires quickly find and kill him. This dark tale, based on Richard Matheson's even darker novel I Am Legend, was later remade as The Omega Man with Charlton Heston in the Vincent Price role.