In the year 1968, Dr. Robert Morgan finds himself in a grim reality where a devastating plague has transformed the majority of the population into undead, vampiric beings who are vulnerable to sunlight, terrified of mirrors, and repelled by garlic. Despite their desire to harm him, these creatures are neither strong nor intelligent. Each day, Morgan follows a monotonous routine: he starts his day by marking off another calendar day, arming himself, and embarking on a grim hunt for these vampires. He systematically eliminates as many as he can, incinerating their bodies to prevent any chance of them rising again. When night falls, he barricades himself within the confines of his home.
Through a haunting flashback, we learn that back in December 1965, tragedy struck as Morgan's wife, Virginia, and daughter, Kathy, fell victim to the plague before the public was aware of the gruesome reality. Choosing to bury Virginia in secret instead of taking her to the public burn pit reserved for his daughter’s remains proved to be a fateful decision. When she later returned home in a monstrous form and attacked him, Morgan realized he must eliminate the plague victims using a wooden stake. He speculates that he gained immunity to the virus when infected by a vampire bat during his military service in Panama, allowing a diluted version of the plague to mingle in his blood.
One fateful day, a dog wanders into the neighborhood, sparking a flicker of hope for companionship. Morgan chases after it but fails to catch it initially. Later, the injured dog appears on his doorstep, and he takes it in, treating its wounds with care—craving contact with another living being after three long years. Unfortunately, he soon discovers that the dog is also infected. Heartbroken, Morgan prepares to bury it, impaled by a stake, sinking deeper into isolation and despair.
As he buries the dog, Morgan's attention is caught by a woman named Ruth who initially flees from him in fear. After some coaxing, she returns to his home but he remains wary of her intentions. His fears are confirmed when she becomes ill at the scent of garlic, explaining that she simply has a sensitive stomach. However, upon further investigation, Morgan finds Ruth attempting to use a blood and vaccine mix that keeps the plague’s effects at bay. She confides in Morgan about her group, who, like her, are infected but receiving treatment. Their agenda involves entrenching themselves within the community as they plan to purge the remaining uninfected humans, indicating that many of the vampires Morgan has dispatched were not truly dead.
Despite Ruth's pleas for him to escape, Morgan remains stubbornly resistant. While she sleeps, he performs a risky transfusion of his own blood into her veins, quickly curing her and igniting a glimmer of hope that they can find a solution for her people. However, chaos erupts when Ruth's companions attack Morgan's home, leading him to just barely escape as Ruth's group kills the remaining vampires near him. In the ensuing chase, armed with a firearm, Morgan utilizes tear gas grenades from a police station to hinder his pursuers. In the end, he finds himself cornered in a church, where a fatal spear is thrown, landing a lethal blow.
In his dying moments, Morgan denounces his adversaries as "freaks," declaring himself the last true man on Earth while Ruth holds him in her arms. After his passing, Ruth notices a baby crying nearby and attempts to reassure the child that safety has been restored.
