Susan and Mary discover Gil's a fanboy of the latest teenage vampire saga, so they transform into vampires to get his attention. Johnny and Dukey turn vampire hunter to rescue Gil and turn Johnny's sisters back to normal. Johnny's frustrated-everyone in his grade is taller than him. He begs the girls to give him a growth injection, which turns him into a hulking beast! Dukey and the girls must change him back before the army can capture him for experiments.