After a group of young girls go missing Sam and Dean realize that a group of vampires have taken up residence in the small town. After a fight with two of the blood-suckers, Dean is bitten and turns into a vampire. Samuel tells Dean he can change him back but he’d have to get the blood of the vampire who turned him. Dean infiltrates the nest and runs into the Alpha...

Dean becomes suspicious of Samuel's motives, but Sam isn't sold on the idea that their grandfather is doing anything wrong. The brothers go along on a hunt with Samuel and the other Campbells, but things go terribly awry.

A chance to take out a nest of vampires backfires when the alpha-vamp shows up and turns the tables on Mary and the British Men of Letters, who are doing their best to recruit Sam and Dean.