Butters is convinced he's seen a vampire at the school. Tired of being picked on by his parents and friends, he is tempted to give himself over to the dark side. Meanwhile, the Goth kids are angry and frustrated when the other kids can't tell the difference between a Goth and a vampire.
The fourth graders are in a computer class are playing Call of Duty: World at War was taught by Mr. Mackey, but nobody that paying attention. Butters mistakes older students following the vampire craze for actual vampires and tries to raise the alarm. Cartman suggests that he go "document the vampires" simply to get rid of him.
Butters sneaks into the school gym and hides to record the members of the South Park Vampires' Club on his tape recorder. One of the vampires talks about vampire-related customs and they "feed" by drinking Clamato juice. However, Butters' tape recorder malfunctions, exposing him in front of the vampires. Butters attempts to repel them with a crucifix before running away.
After an unfair grounding from his parents, Butters thinks aloud, concluding that nobody listens to him. Having come to believe that if he becomes a vampire he will no longer get victimized, he asks the vampire kids to let him join them. They take him to Hot Topic and change his appearance to match theirs. Butters returns home to his parents, who are angry at him because of his lateness and his dyed hair. Butters responds that he is now "ungroundable" and hisses at his parents, thus completely shocking them.
Shortly after, Butters starts wasting away because he believes he can only feed on blood. He sneaks into Cartman's room in the middle of the night in a failed attempt to "feed," only managing to give Cartman a Love-bite. Butters' parents, alerted by Cartman's mother, ask him if he "got gay with one of his schoolmates that night". Stephen attempts to confine Butters to his bedroom, but he simply leaps out of the window.
Throughout this episode, the school's Goth kids loathe the vampire kids with whom they keep getting confused by everyone, including Principal Victoria. Reluctantly, they decide to switch to a casual look to clear the confusion, but change their mind when they hear someone from the school soccer team describing them as "that fat girl, the big nose kid, the midget and the kid with pock marks on his face", which had caused them to become Goths in the first place. After discussing what they could do to stop the vampire craze, the Goth kids decide to get rid of "the head vampire", fifth grade student Mike Makowski, whom they kidnap and mail to Scottsdale. This however fails to solve the problem and just when the Goth kids are about to face defeat from the vampire kids, Butters informs them that Hot Topic is the source of the vampire craze. He takes them there and they burn down the store.
At home, Butters tells his parents that the Goth kids burnt down the Hot Topic and this has now "reverted" back to human and he becomes "groundable" once more, much to this parents' relief. In the end, the Goth kids ask for a school assembly in order to explain to everyone the differences between Goth kids and "douchebag vampire wanna-be boner" kids, exclaiming, "Because anyone who thinks they are actually a vampire is freaking retarded." They receive a standing ovation, with the eldest Goth kid closing their speech with, "Fuck all of you" and flipping everyone off.
The head "vampire" often says "per se" which seems to be a reference to an episode of Tyra that deals with vampires, in which one of the vampires frequently says "per se".