Alpha Bitch: The victim was "chosen" by the mysterious vampire and she turned into a popular girl who is haughty and mean to her classmates. When Amy first arrived at the school, she was scared and alone, but was befriended by Arlene. However after meeting the "vampire", their situations at the school reverse, and Amy suddenly became the most popular girl in school. She used her newfound status to humiliate Arlene.
Desperately Craves Affection: If Arlene's crush on Murdoch can be taken at face value, when combined with Arlene never being "chosen" by the vampire when other girls were, the episode implies she has deeper emotional issues that may have led to her lashing out and killing Amy after the latter betrayed and humiliated her in front of their classmates.
Hemo Erotic: The girls are all crazy for the mysterious vampire who sucks their blood.
Mr. Exposition: Darcy Garland serves as this when he tells Murdoch and the audience about the past of a doctor involved in the case, including his work on blood transfusions.
Our Vampires Are Different: The murderer is believed to be a vampire in the wake of the latest literary craze Dracula. But it was merely the work of an unscrupulous doctor.
Precocious Crush: Arlene is a teenager who develops a crush for adult Murdoch. It may have been an attempt to distract him from his investigation and throw him off her trail, rather than a genuine interest in him.
Pursued Protagonist: The opening scene shows a disheveled girl running through the woods and collapsing facedown in a fountain as a figure looms over her. In a twist, it turns out that her pursuer meant her no harm and even pulled her out of the water, but someone else drowns her once he leaves.
"Scooby-Doo" Hoax: The "vampire" is a haemophiliac young man being treated with transfusions of blood taken by his doctor from the abducted girls.
Strong Family Resemblance: The "vampire" is suffering from the same medical ailment as his grandfather, and looks very much like him. This is the basis for Crabtree mistakenly thinking they're the same person who's been sucking young womens' blood.
