Three days before my flight to Serbia, the Devil intervenes: my mother, who is supposed to meet me in Belgrade, falls into a chasm on a Moscow sidewalk and shatters her ankle. That she has gone through life without ever having broken a bone before makes her, according to her own mother, a casualty of my intentions. It is a bad sign. My grandmother, waiting for me in Belgrade, advises me to cancel my trip; her fears are reinforced the following morning by a phone call from one of my Serbian contacts—a journalist who was supposed to meet with me has gotten wind of my mother’s accident and pulled out of her agreement to help. “What now?” my grandmother asks, and fumes when she hears that I am determined to press on.

It may seem strange that I have returned to the Balkans to hunt for vampires when I get so many of them in my adoptive homeland. Since immigrating to the States in 1997, I have formed an uneasy acquaintance with the legion undead peopling the American imagination: Anne Rice’s beautiful, tortured ghouls; Buffy’s ridge-faced villains and morally confused male leads; countless cinematic and literary variations on Bram Stoker’s nightwalker, from Elizabeth Kostova’s historical reinterpretation of Vlad Tepes to Francis Ford Coppola’s shape-shifting, costume-changing warrior-beast. But the power of the newest trend is incredible: vampires of all shapes, sizes, convictions, and denominations are swelling the national bestiary. My undergraduate students at Cornell deny reading Stephenie Meyer, but whenever I ask them to compose lists of their favorite books, it seems like fully half include Darren Shan’s The Vampire’s Assistant. My office window looks over the Commons and into the living room of a young woman from whose walls Twilight’s Robert Pattinson leers up, his smile signaling with indecently little ambiguity that it is sexytime.

Two days later, when I call to tell my grandmother I’ve missed my connecting flight in Paris, she an...