A deadly virus turns most of the world's population into blood-drinking ghouls.

A strange plague hits the earth and turns the survivors into vampires, with the exception of Robert Morgan, a scientist who many years before contracted a fever that made him immune to the plague. Morgan's daily routine is to clear the streets of dead bodies and to seek out the vampires, who sleep by day, and drive stakes through their hearts. At night he wards off the roaming vampires with mirrors and garlic. One day he meets Ruth, a young woman who is apparently also immune, but he learns that she is one of a group of vampires who possess a serum that provides them with temporary relief from their vampirism. Morgan returns Ruth to normal by giving her a transfusion of his own blood. She informs him that members of her group are coming to destroy him, and, although he warns them that he is their only hope for a return to normalcy, they kill him.