When the villagers of Kleinschloss start dying of blood loss, the town fathers suspect a resurgence of vampirism, but police inspector Karl Breettschneider remains skeptical. Scientist Dr. Otto von Niemann, who cares for the victims, visits a patient who was attacked by a bat, Martha Mueller. Martha is visited by a mentally challenged man named Herman Glieb, who claims he likes bats because they are "soft like cat" and "nice".