A plague has wiped out most of mankind, and those who survived have become bloodthirsty vampires. The only "normal" human left on earth, Dr. Robert Morgan (Vincent Price) — who was spared by a twist of fate -- spends his days methodically hunting down the undead mutants and his nights barricaded against their attacks. But when he meets the beautiful but contaminated Ruth, he discovers a secret that will unravel what’s left of his existence.